JP2008226424A - Perpendicular recording magnetic head and magnetic disk apparatus - Google Patents

Abstract

The present invention provides a perpendicular recording magnetic head that further improves the magnetic characteristics when writing magnetic data by magnetizing a magnetic recording medium in the perpendicular direction.
A recording magnetic field output surface of a main magnetic pole for emitting a recording magnetic field generated by an exciting coil in a perpendicular recording magnetic head in a perpendicular direction toward a magnetic recording medium is closer to a trailing side than a bottom side on a leading side. It has a trapezoidal shape with a long base, and further has a distribution in which the saturation magnetic flux density decreases from the trailing side to the leading side, thereby contributing to improvement in recording density.
[Selection] Figure 4

Description

  The present invention relates to a perpendicular recording magnetic head and a magnetic disk apparatus, and more particularly to a perpendicular recording magnetic head and a magnetic disk apparatus used for recording magnetic data on a magnetic recording medium.

  In a magnetic disk apparatus, it is well known to record and reproduce magnetic data on a magnetic recording medium, for example, a magnetic disk, using a magnetic head, but in order to increase the storage capacity per unit area in the magnetic disk. Therefore, it is necessary to improve the recording density in both the track width direction and the bit length direction.

  However, in the currently used in-plane recording methods, it is known to reduce the bit length by reducing the recording layer in order to increase the recording density. Thermal fluctuation is likely to occur, which hinders high recording density.

  As a method for solving this problem, a perpendicular recording system in which magnetic information is recorded by magnetizing a magnetic recording medium in a perpendicular direction is considered promising.

  In the perpendicular magnetic recording method, the area of each magnetic domain on the surface of the recording layer is smaller than in the in-plane recording method, so that a higher recording density can be achieved. Furthermore, since the magnetization is oriented in the direction perpendicular to the film surface of the recording layer, even if the recording layer is thickened, the recording density does not decrease, and even when the recording layer is made thin, the thermal fluctuation phenomenon is unlikely to occur. .

  Even in such a perpendicular recording system, it is necessary to increase the coercivity of the recording layer in order to obtain a high-quality recording / reproducing signal at a higher recording density. In addition, since the perpendicular recording method needs to generate high data recording magnetization, a soft under layer (SUL) that plays a role of refluxing the perpendicular recording magnetic field is provided below the recording layer.

  Providing such a soft magnetic backing layer increases the writing ability of the magnetic head disposed on the recording layer, and can generate a recording magnetic field exceeding 10 Tesla (T). Writing can also be performed on a recording layer having a relatively large holding force exceeding kilo-Oersted (kOe).

  As a reproducing magnetic head for reproducing in the perpendicular recording system, a giant magnetoresistive (GMR) effect type head and a tunneling magnetoresistive (Tunneling Magneto Resistive: TMR) having a large reproducing output are used as in the in-plane recording system. An effect type head or the like can be used.

  Even in the case of the perpendicular recording method as described above, it is still necessary to improve the density in both the track width direction and the bit length direction in order to further improve the recording density in the future. Among them, in order to improve the density in the track width direction, it is necessary to control the core width of the magnetic head with high accuracy.

  In particular, in the case of perpendicular recording, in principle, the shape of the air bearing surface at the tip of the main pole constituting the recording magnetic head greatly affects the magnetization pattern of the magnetic recording medium. The main pole has a planar shape as shown in FIG. 26, for example.

  The main magnetic pole 100 shown in FIG. 26 includes a rectangular yoke part 100a formed above the magnetic field generating coil 110, a throttle part 100b protruding from the tip of the yoke part 100a and narrowed in a tapered shape, and a throttle part 100b. And a tip portion 100c having a floating surface 101 at the tip.

  The leading end surface of the main pole of the recording magnetic head and the main part of the recording surface of the magnetic recording medium have a positional relationship as shown in the plan view of FIG. 27, for example.

  In FIG. 27, reference numeral 101 denotes a floating surface of the tip 100c of the main magnetic pole 100, reference numeral 101a denotes a leading edge of the floating surface 101, reference numeral 101b denotes a trailing edge of the floating surface 101, and reference numerals 102a and 102b denote magnetic disks. Reference numeral 103 denotes a track pitch, and reference numeral 104 denotes a yaw angle which is an inclination of the air bearing surface 101 with respect to the tangent to the tracks 102a and 102b of the magnetic disk. In a standard magnetic disk device, the yaw angle 104 is in a range of about ± 15 ° to 20 ° at the maximum.

  The air bearing surface 101 of the main magnetic pole 100 shown in FIG. 27 has an inverted trapezoidal shape in which the bottom on the trailing side is wider than the bottom on the leading side, as described in Patent Document 1 below. As described above, Patent Document 1 describes that by making the air bearing surface 101 into an inverted trapezoidal shape, it is possible to reduce the influence of the tip portion 100c protruding from the track due to the yaw angle 104. The air bearing surface 101 is a surface facing the surface of the recording layer, and constitutes an air bearing surface (ABS) or a part of the medium facing surface of the magnetic head.

  However, the leading edge 101a of the air bearing surface 101 of the main magnetic pole 100 scanning the track 102a protrudes into the adjacent track 102b due to the presence of the yaw angle 104, as shown in FIG. In this case, as a matter of course, there is a high possibility that the magnetic information in the adjacent track 102b is erased.

  In the future, with the demand for higher recording data density, the widths of the tracks 102a and 102b will become smaller and the bit length along the tracks 102a and 102b will become shorter and shorter. As a result, when the shape of the air bearing surface 101 of the main magnetic pole 100 is inverted trapezoidal, the head magnetic field is inevitably lowered, and noise increases as the air bearing surface 101 approaches the track edge. .

  On the other hand, in order to increase the recording capability, a main magnetic pole of a type in which a magnetic material layer having a high saturation magnetic flux density is laminated on the upper surface of the wide trailing edge of the inverted trapezoidal tip 100c of the main magnetic pole 100. The shape is described in Patent Document 2. The magnetic material layer is formed to have the same width as the trailing edge.

  Further, even if the geometrical protrusion from the tracks 102a and 102b due to the yaw angle 104 is not taken into consideration, when the track width is further narrowed, the adjacent magnetic tracks are spread by the spread of the magnetic field from the leading edge 101a. This signal is easily erased. In addition, since the magnetic material used for the main magnetic pole 100 is restricted by the saturation magnetic flux density, the vertical strength of the head magnetic field passing through the tip 100c of the main magnetic pole 100 is also restricted.

  Therefore, in the magnetic disk device, as a means for ensuring an efficient, stable and high-performance recording operation, it is necessary to control the magnetic flux so that an excessive magnetic flux is not supplied to the tip portion 100c of the main magnetic pole 100.

  This is because if magnetic flux saturation occurs at the tip portion 100c of the main magnetic pole 100, unnecessary magnetic flux (magnetic field) is emitted from the side portion other than the air bearing surface 101, and information recorded on the adjacent track may be rewritten. Because there is.

  In order to increase the magnetic flux supplied to the tip portion 100c of the main magnetic pole 100, the auxiliary magnetic pole layer is sandwiched between a part of the yoke part 100a and a part of the taper part 100b of the main magnetic pole 100 with a nonmagnetic layer interposed therebetween. Is described in Patent Document 3. However, the auxiliary magnetic pole layer does not suppress an unnecessary magnetic field spreading around the tip portion 100 c of the main magnetic pole 100.

Further, Patent Document 4 discloses that the auxiliary magnetic pole layer 111 is formed in direct contact with the main magnetic pole 100 under the yoke portion 100a. The auxiliary magnetic pole layer has the same planar shape as that of the yoke portion 100a, accommodates the main magnetic flux in the auxiliary magnetic pole layer, and further passes the magnetic flux accommodated in the auxiliary magnetic pole layer through the narrowed portion 100b ahead of the tip portion 100c. It has the function to supply to.
Japanese Patent Laid-Open No. 2002-92821 JP 2005-183002 A JP 2004-164715 A JP 2006-155867 A

  However, in order to further increase the recording density in the magnetic recording apparatus, it is necessary to further suppress the spread of the write magnetic field caused by a magnetic field exceeding the saturation magnetic flux density or a change in the yaw angle.

  An object of the present invention is to provide a perpendicular recording magnetic head and a magnetic disk apparatus that can further improve the magnetic characteristics when writing magnetic data by magnetizing a magnetic recording medium in the perpendicular direction.

According to one aspect of the present invention, a recording magnetic field output surface having a trapezoidal shape in which the bottom on the trailing side is longer than the bottom on the leading side and the saturation magnetic flux density distribution is small from the trailing side to the leading side. A perpendicular recording magnetic head having a first magnetic pole is provided.
According to another aspect of the present invention, there is provided a perpendicular recording magnetic head mounted on a slider having a medium facing surface, wherein the head is magnetically coupled in this order from the medium facing surface to a tip portion, a diaphragm portion, and a yoke portion. Includes a planar first magnetic pole including a recording core and at least a yoke portion of the first magnetic pole, and the planar width is longer than the length of the recording core in the direction perpendicular to the core width direction. There is provided a perpendicular recording magnetic head including a second magnetic pole formed with a long length in the direction.
According to still another aspect of the present invention, there is provided a perpendicular recording magnetic head mounted on a slider having a medium facing surface, wherein the head is magnetically coupled in the order from the medium facing surface to a tip portion, a diaphragm portion, and a yoke portion. The first magnetic pole having a saturation magnetic flux density that decreases from the ring side toward the leading side and the first magnetic pole are magnetically coupled to at least the yoke portion, and the planar shape is perpendicular to the core width direction of the recording core. There is provided a perpendicular recording magnetic head having a second magnetic pole formed with a length in a core width direction longer than a length in a direction.

According to the feature of the present invention, since the saturation magnetic flux density in the first magnetic pole of the perpendicular recording magnetic head is distributed so as to decrease from the trailing side to the leading side, the presence of the recording magnetic field output yaw angle is taken into consideration. Even in this case, interference with adjacent tracks can be reduced, the recording density in the track width direction can be improved, and the bit length direction can be achieved by writing with a steep magnetic field at the trailing edge. Recording density can be improved.
Also, for the problem that signal erasure occurs due to the residual magnetization of the first magnetic pole immediately after recording, a magnetic material having a good soft magnetic property showing a low coercive force Hc and a low anisotropic magnetic field Hk is mainly used. This can be overcome by occupying 50% or more of the entire magnetic pole.
Furthermore, if a non-magnetic layer having a thickness of 2 to 5 nm is inserted between the laminated magnetic layers of the first magnetic pole, the above problem can be further improved, and the recording frequency corresponding to high-speed data transfer can be improved. There is a significant advantage in terms of high frequency.
According to another feature of the present invention, the second magnetic pole magnetically coupled to the first magnetic pole when the magnetic recording medium is magnetized in the perpendicular direction from the first magnetic pole of the perpendicular recording magnetic head to write magnetic data. Is placed closer to the medium facing surface than in the past, the magnetic saturation position can be positioned closer to the medium facing surface than in the past, and the spread of the saturation write magnetic field can be suppressed compared to the conventional case. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a plan view showing an example of the internal structure of the magnetic disk device according to the embodiment of the present invention, and the relationship between the magnetic head and the magnetic disk is clarified.

  In FIG. 1, a slider 13 is fixed to the tip of a suspension arm 12 supported by a rotary actuator 11 in a housing 10. A slider 13 is fixed to the tip of the suspension arm 12 via a support called a gimbal which is omitted in the drawing. A magnetic head element portion 14 to be described later is fixed to the end portion of the slider 13.

  The magnetic head element unit 14 records (writes) and reproduces (reads) information on a magnetic disk (magnetic recording medium) 15 that rotates counterclockwise in FIG. Note that the arrows in FIG. 1 indicate the direction of rotation of the magnetic disk 15.

  The magnetic head element unit 14 has a perpendicular recording head in which a write shield is disposed on the trailing side of the main magnetic pole, and a reproducing head using a magnetoresistive element, a tunnel magnetoresistive element, or the like.

  The magnetic head element unit 14 is moved to a different radial position of the magnetic disk 15 and positioned by the rotation of the rotary actuator 11. At this time, a plurality of concentric recording tracks are generated on the magnetic disk 15. To improve the density in the track width direction means to form a plurality of concentric recording tracks at a constant narrow interval.

  The movement of the rotary actuator 11 described above is the movement of the magnetic head element unit 14. Accordingly, since the recording / reproducing bit is determined based on the relationship between the movement of the magnetic head element section 14 and the movement of the magnetic disk 15, in principle, the angle between the magnetic head and the recording track depending on the disk radial position, that is, The yaw angle changes variously, and changes by ± 15 ° to 20 ° at the maximum.

  FIG. 2 is a cross-sectional view of the main part showing the flow of magnetic flux between the magnetic head and the magnetic disk at the time of perpendicular recording in the magnetic disk apparatus according to the embodiment of the present invention and showing the principle of perpendicular magnetic recording. The same symbols as used in the above description indicate the same parts or have the same meaning.

  In FIG. 2, a recording magnetic head 27 composed of a main magnetic pole 21, an auxiliary magnetic pole 22, and a conductive coil 23 is disposed opposite to the recording layer 33 of the magnetic disk 15 having a perpendicular recording structure. As shown by the wavy line in FIG. 2, the auxiliary magnetic pole 22 constitutes a part of the path of the magnetic field passing through the tip of the main magnetic pole 21 and the magnetic disk 15, and is also called a return yoke.

The magnetic disk 15 has a backing layer 32 made of a soft magnetic layer formed on a substrate 31 made of a nonmagnetic material, and a recording layer 33 formed on the backing layer 32.
The perpendicular recording magnetic head 27 has a structure in which the conductive coil 23 is disposed on both the leading side and the trailing side of the main magnetic pole 21 as will be described later.

  When current is passed through the conductive coil 23 of the recording magnetic head 27 to excite it, a magnetic field perpendicular to the surface of the recording layer 33 is generated between the front end surface of the main pole 21 and the backing layer 32, thereby causing perpendicular recording. The recording layer 33 of the magnetic disk 15 having the structure is magnetized in the vertical direction to record data.

  A plurality of rectangular broken lines indicated by a symbol A shown in FIG. 2 indicate a flow path of magnetic flux, and the magnetic field flowing into the soft magnetic underlayer 32 returns to the main magnetic pole 21 via the auxiliary magnetic pole 22 and returns to the magnetic circuit. Configure. At this time, the magnetization state recorded on the magnetic disk 15 depends on the shape of the main magnetic pole on the air bearing surface of the magnetic recording head 27 facing the magnetic disk 15, and in particular, the traveling direction of the magnetic disk indicated by the arrow B It can be seen that recording is performed on the downstream side with respect to the (rotation direction), that is, on the trailing side edge of the main magnetic pole 21.

  The schematic configuration of the magnetic disk device shown in FIG. 1 and the principle diagram of perpendicular magnetic recording shown in FIG. 2 are also applied to each of a plurality of embodiments to be described later, except for the configuration of the magnetic head element unit 14. .

FIGS. 3A and 3B are main part explanatory views showing the whole of the perpendicular magnetic recording head according to the first embodiment of the present invention. FIG. 3A is a main part for explaining the configuration of the air bearing surface of the perpendicular magnetic recording head. FIG. 3B is a partial plan view showing a longitudinal section of a main part of a side surface for explaining the configuration of the air bearing surface of the perpendicular magnetic recording head. The same reference numerals as those used in FIGS. 1 and 2 indicate the same parts. Or have the same meaning.
3A shows the air bearing surface of the perpendicular magnetic recording head, the magnetic disk is positioned at the front side of the drawing at a slight distance from the paper surface.

  3A and 3B, reference numeral 24 denotes a write shield, reference numerals 25a and 25b denote first and second auxiliary magnetic poles, and reference numeral 26 denotes a reproducing magnetic head. For the reproducing magnetic head 26, a GMR effect element or a magnetoresistance effect element 26a of a TMR effect element is used.

  The perpendicular recording magnetic head 27 is formed on the reproducing magnetic head 26 formed on a nonmagnetic substrate (illustrated) via an insulating separation layer 28. The reproducing magnetic head 26 includes a nonmagnetic insulating gap layer 26c that sandwiches the magnetoresistive effect element 26a and first and second reproducing magnetic shield layers 26b and 26d that sandwich the nonmagnetic insulating gap layer 26c. .

  The perpendicular recording magnetic head 26 includes a first conductive coil 23a embedded in the first insulating layer 29 on the first auxiliary magnetic pole 25a, a main magnetic pole 21 formed above the first insulating layer 29, A nonmagnetic gap layer 30 covering the main pole 21, a second insulating layer 31 formed on the gap layer 30, a second conductive coil 23b embedded in the second insulating layer 31, and a second A second auxiliary magnetic pole 25b formed on the insulating layer 31; and a write shield 24 connected to the tip of the second auxiliary magnetic pole 25b and formed on the gap layer 30.

  4A and 4B are enlarged explanatory views of the main magnetic pole and its vicinity in the perpendicular recording magnetic head described with reference to FIGS. 3A and 3B. FIG. 4A is a diagram for explaining the configuration of the air bearing surface of the main magnetic pole. 4B is a plan view of the main part, and shows a vertical cross section of the main part. The parts indicated by the same symbols as those used in FIGS. 1, 2, 3A and 3B represent the same or equivalent parts. And

  The main magnetic pole 21 in the perpendicular recording magnetic head of the present invention shown in FIGS. 4A and 4B is characterized by its characteristics. That is, the main magnetic pole 21 has a tip having an inverted trapezoidal shape from the leading side to the trailing side, and the saturation magnetic flux density Bs continuously increases in the film thickness direction from the leading side to the trailing side. The selected magnetic material is laminated to give a gradient to the saturation magnetic flux density Bs.

  That is, in the illustrated example, the main magnetic pole 21 is composed of a laminated film made of at least three materials having different saturation magnetic flux densities Bs, and the saturation magnetic flux density Bs in the magnetic layer 21A in the vicinity of the trailing edge is 2.0 T or more. The magnetic layer 21C in the vicinity of the leading edge is preferably made of a magnetic material of 1.0 T or less, and the ratio of the saturation magnetic flux density Bs of the magnetic layer 21A on the trailing edge side to the magnetic layer 21C on the leading edge side is 2 It is desirable that the number be 0 or more.

  As a specific example, FeCo having a saturation magnetic flux density Bs = 2.4T is used as the magnetic layer 21A on the trailing edge side, and NiFe (Ni composition having a saturation magnetic flux density Bs = 1.0T is used as the magnetic layer 21C on the leading edge side. = 70 wt% (wt.%) To 80 wt.%), And FeNi with a saturation magnetic flux density Bs = 2.1 T (Fe composition = 80% to 90%) as the intermediate magnetic layer 21B. ) Can be used.

In such a configuration, as a matter of course, the magnetic resistance is small in the magnetic layer 21A on the trailing side, and the magnetic resistance is large in the magnetic layer 21C on the leading side.
In FIG. 4B, a main magnetic pole auxiliary layer 21S is formed on the leading edge side surface of the magnetic layer 21A. Here, when the main magnetic pole 21 is the first magnetic pole and the main magnetic pole auxiliary layer 21S is the second magnetic pole, the auxiliary magnetic pole 22 is the third magnetic pole.

As shown in the plan view of FIG. 4C, the main magnetic pole auxiliary layer 21S is formed so as to overlap only on the square yoke portion 21x of the main magnetic pole 21. A portion of the yoke portion 21x that constitutes the main magnetic pole auxiliary layer 21S on the air bearing surface side is formed with a narrowed portion 21y whose width is narrowed forward and protrudes from the narrow tip of the narrowed portion 21y to the tip. A tip portion 21z having an air bearing surface is formed to protrude.
As the structure of the perpendicular recording magnetic head excluding the main magnetic pole 21 and the main magnetic pole auxiliary layer 21S, the structure shown in the second embodiment to be described later may be adopted.

  The main magnetic pole auxiliary layer 21S disposed on the leading edge side of the main magnetic pole 21 is for efficiently concentrating the magnetic flux in the vicinity of the trailing edge of the main magnetic pole 21 as shown by the arrow surrounded by the broken circle in FIG. 4B. It is arranged in.

  FIG. 5 is a plan view of the main part showing the main pole assumed for performing the magnetic field simulation on the perpendicular recording magnetic head as viewed from the air bearing surface.

FIG. 5A shows the main pole of the present invention, and FIG. 5B shows the main pole according to the prior art.
In the case of FIG. 5A, the recording core width at the trailing edge at the tip of the inverted trapezoidal shape of the main magnetic pole 21 is assumed to be 135 nm. Further, when the total film thickness of the main magnetic pole 21 is 250 nm, the saturation magnetic flux density Bs in the magnetic layer 21A in the part of the film thickness 50 nm from the trailing edge is 2.4 T, and the magnetic layer in the part of the film thickness 50 nm from the leading edge. It is assumed that the saturation magnetic flux density Bs at 21C is 1.0T, and that the intermediate magnetic film 21B has a thickness of 150 nm and the magnetic layer 21B has a saturation magnetic flux density Bs of 2.1T.
In the case of FIG. 5B, the simulation was performed assuming that the entire main magnetic pole 121 is made of the same magnetic material and the saturation magnetic flux density Bs is 2.1T.

6A and 6B are diagrams showing a two-dimensional head magnetic field distribution showing simulation results performed on the main magnetic poles 21 and 121 shown in FIGS. 5A and 5B, respectively. 6A corresponds to the main magnetic pole 21 of the first embodiment of the present invention shown in FIG. 5A, and FIG. 6B corresponds to the main magnetic pole 121 of the conventional example shown in FIG. 5B.
6A and 6B, the outline of the main magnetic poles 21 and 121 is indicated by a broken line.

FIG. 7 shows the head magnetic field distribution in the down-track direction at the track center of the magnetic disk by comparing the main magnetic pole according to the present invention (solid line) and the main magnetic pole according to the prior art (broken line).
In FIG. 7, the vertical axis indicates the magnetic field (unit: kOe), and the horizontal axis indicates the distance in the down track direction (unit: μm). The arrow H indicates the magnetic field strength from the reading side. The reduction of the magnetic field strength reaches 17%.

  According to the main magnetic pole of the magnetic head according to the first embodiment of the present invention shown in FIG. 6A, the magnitude of the leakage magnetic field near the leading edge is suppressed as compared with the main magnetic pole according to the conventional technique shown in FIG. 6B. I can see that.

  According to FIG. 7, in the head magnetic field distribution in the down track direction, the magnetic field strength in the vicinity of the trailing edge in the main pole of the present invention is equivalent to the magnetic field strength in the vicinity of the trailing edge in the main pole of the conventional example. However, it can be seen that the magnetic field intensity near the leading edge is suppressed by about 17%.

  In addition to the above advantages, it has been confirmed that the head magnetic field gradient that determines the transition width of the magnetic disk can be improved by about 3% by adopting the configuration of the main pole in the magnetic head of the present invention.

  As described above, according to the main magnetic pole in the magnetic head according to the first embodiment of the present invention, the influence of the magnetic field spreading from the leading edge is reduced even when the yaw angle is taken into consideration. In addition, a sufficiently large head magnetic field can be generated at the trailing edge of the main pole, and a large magnetic field gradient can be obtained, so that the density in the bit length direction can also be improved. Can do.

  In addition, for the problem that signal erasure occurs due to the main magnetic pole remanent magnetization immediately after recording, a magnetic material having a good soft magnetic characteristic showing a characteristic of a low coercive force Hc and a low anisotropic magnetic field Hk is used. This can be overcome by occupying 50% or more of the thickness. Further, when a nonmagnetic layer having a thickness of 2 nm to 5 nm is interposed between the laminated films of the main magnetic pole, further improvement is possible.

  Furthermore, in view of increasing the recording frequency corresponding to high-speed data transfer, in order to further reduce the hysteresis loss and eddy current loss of the main magnetic pole, the low coercive force Hc, the low anisotropic magnetic field Hk, and the high resistance Since the ratio ρ and the high saturation magnetic flux density Bs are generally required, a low coercive force Hc and a low difference are obtained by interposing a nonmagnetic layer having a thickness of 2 nm to 5 nm between the laminated films of the main magnetic poles. Since the material can be controlled to the isotropic magnetic field Hk and the material having a high saturation magnetic flux density Bs is arranged at the trailing edge, a magnetic head capable of handling high frequency recording is realized.

  As described above, the perpendicular recording magnetic head according to the first embodiment of the present invention has an inverted trapezoidal shape in which the width of the main magnetic pole, particularly the tip thereof, increases from the leading side to the trailing side. The magnetic material having a saturation magnetic flux density Bs increased continuously or stepwise is laminated in the film thickness direction from the leading side to the trailing side.

  With this configuration, it is possible to suppress the magnetic field spread in the vicinity of the leading edge in the main pole, and the influence of the yaw angle on the adjacent track can be reduced. Further, the main magnetic pole is formed of a magnetic material having a saturation magnetic flux density Bs of 2.0 T or more in the vicinity of the trailing edge and a saturation magnetic flux density Bs of 1.0 T or less in the vicinity of the leading edge. A gradient of the saturation magnetic flux density Bs was provided in the direction, and the magnetic field distribution at the trailing edge could be made steep.

  Therefore, even when the yaw angle is considered, bleeding (interference) to adjacent tracks can be reduced, and improvement in density in the track width direction can be expected. At the same time, writing is performed with a steep magnetic field at the trailing edge. Therefore, it is possible to improve the density in the bit length direction, and to provide a magnetic disk device capable of recording / reproducing with high density.

By the way, when the main magnetic pole 21 is composed of a plurality of magnetic layers having different saturation magnetic flux densities, the plurality of magnetic layers may adopt a structure formed through a nonmagnetic material layer, for example, a ruthenium (Ru) layer. Good.
Next, two examples of the method for creating the main magnetic pole of the magnetic recording head according to the first embodiment of the present invention will be described. For the formation process other than the main magnetic pole, for example, the process shown in the second embodiment is adopted.

Example 1
8A to 8E are main part side views showing Example 1 of the process of manufacturing the main magnetic pole according to the first embodiment of the present invention. Hereinafter, description will be given with reference to these drawings.

First, as shown in FIG. 8A, by applying the sputtering method, the magnetic layer constituting the main pole is laminated on the Al ₂ O ₃ film as the inorganic insulating film 41 in order from the material with the lowest saturation magnetic flux density Bs. Film. Specifically, the first magnetic layer 42 having a thickness of 20 to 50 nm made of FeNi (Fe composition = 70 wt.% To 80 wt.%) Corresponding to the saturation magnetic flux density Bs = 1.0 T is specifically mentioned. Saturation magnetic flux density Bs = 2.1T equivalent FeNi (Fe composition = 80 wt.% To 90 wt.%) Second magnetic layer 43 having a thickness of 150 nm to 200 nm, high saturation flux density Bs = 2.4 T This is a third magnetic layer 44 having a thickness of 40 nm to 60 nm made of FeCo (composition of Fe = 60 wt.% To 80 wt.%) Having a magnetic flux density Bs.

  Next, as shown in FIG. 8B, a resist film 45 having a pattern having the same width as the trailing side width of the main pole is formed on the third magnetic layer 44 by applying a resist process in the lithography technique. To do.

Subsequently, as shown in FIG. 8C, by applying an ion milling method, the third magnetic layer 44, the second magnetic layer 43, and the first magnetic layer 42 are anisotropically etched using the resist film 45 as a mask. Thus, the inverted trapezoidal main magnetic pole 46 is formed. In this case, the whole including the tip of the main magnetic pole 46 has an inverted trapezoidal shape.
Note that the ion milling method may be replaced with a dry etching method in which an etching gas is appropriately selected. Specifically, alumina, that is, an inorganic insulating film such as Al ₂ O ₃ or SiO _{2 is used} as a mask, and the reactive property is changed. Ion etching can be applied.

Further, as shown in FIG. 8D, by removing the resist film 45 and applying the CVD method, an inorganic insulating film 47 such as alumina or SiO ₂ is formed on the entire surface to cover the main magnetic pole 46. Then, polishing for planarizing the inorganic insulating film 47 is performed by applying a chemical mechanical polishing (CMP) method.

  Polishing of the inorganic insulating film 47 is performed so as to leave a thickness necessary for generating a gap 47G between the main magnetic pole 46 and the trailing write shield. Here, the trailing-side write shield is necessary to make the magnetic field distribution in the bit length direction steep. Incidentally, the gap 47G is preferably about 40 to 60 nm.

  After the polishing of the inorganic insulating film 47 enabling the generation of the gap 47G through such a polishing process, as shown in FIG. 8E, a plating method or a sputtering method is performed on the polishing surface of the inorganic insulating film 47. By applying, a magnetic material film having a saturation magnetic flux density Bs of 1.4T to 1.8T is formed, and the magnetic material film is used as the write shield 48.

  As shown in FIGS. 3A and 3B, the magnetic flux generated by the coil 23 can be efficiently collected at the trailing edge of the main magnetic pole 46 formed as described above, and a sufficiently large head magnetic field is generated. In addition, a large magnetic field gradient can be obtained. This makes it possible to improve the recording density in the bit length direction.

Example 2
9A to 9D are side views showing the main part of Example 2 of the process of manufacturing the main magnetic pole according to the first embodiment of the present invention, and the same reference numerals as those used in FIGS. 8A to 8E are used. The parts represent the same or equivalent parts. Hereinafter, description will be given with reference to these drawings.

First, as shown in FIG. 9A,
FeNi equivalent to the saturation magnetic flux density Bs = 1.0 T acting as a base film when the plating method is performed on the Al ₂ O ₃ film 51 which is an inorganic insulating film by applying the sputtering method (Fe composition = 80 wt. % To 90 wt.%) Of the first magnetic layer 52 having a thickness of 20 nm to 50 nm.

  Next, by applying a resist process in lithography technology, a resist film 53 is formed on the first magnetic layer 52 by patterning an opening 53A having an inverted trapezoidal cross section for forming an inverted trapezoidal main pole. .

Further, as shown in FIG. 9B, by applying the plating method, the second plating is performed while increasing the composition ratio x of the Fe element among the Fe element and Ni element in the material made of Fe _x Ni _y . The magnetic layer 54 is formed. Accordingly, the saturation magnetic flux density Bs of the second magnetic layer 54 is continuously increased in the film thickness direction from the leading side to the trailing side.

  Subsequently, by applying a plating method, a 40 nm to 60 nm thick layer of FeNi (Fe composition = 80 wt.% To 90 wt.%) Having a saturation magnetic flux density Bs of 2.2 T is provided in the vicinity of the trailing edge. The third magnetic layer 55 is formed on the second magnetic layer 54. As the third magnetic layer 55, a magnetic material made of FeCo (Fe composition = 60 wt.% To 80 wt.%) And having a large saturation magnetic flux density Bs of 2.4 T may be used.

  Further, after removing the resist film 53, as shown in FIG. 9C, by patterning the first magnetic layer 52, which was the plating base film, using the second and third magnetic layers 54 and 55 as masks, An inverted trapezoidal main magnetic pole 56 in which the gradient of the saturation magnetic flux density Bs continuously changes in the film thickness direction from the leading side to the trailing side can be realized. Accordingly, the main magnetic pole 56 has an inverted trapezoidal air bearing surface composed of the first, second and third magnetic layers 52, 53 and 54.

Next, by applying a CVD method, an inorganic insulating film 57 such as alumina or SiO ₂ is formed on the entire surface to cover the main magnetic pole 56. Subsequently, as shown by a broken line in FIG. 9C, polishing for planarizing the upper surface of the inorganic insulating film 57 is performed by applying a CMP method. The upper surface of the main magnetic pole 56 becomes the trailing edge of the main magnetic pole 56, and the inorganic insulating film 57 immediately above the main magnetic pole 56 becomes a gap 57G between the write shield 58 and the main magnetic pole 56 described later.

  Further, a write shield type perpendicular recording magnetic head is realized by forming a write shield 58 on the main magnetic pole 56 via a gap 57G by applying a sputtering method or a plating method. The gap 57G is about 40 to 60 nm.

  The perpendicular recording magnetic head of Example 2 having the main magnetic pole 56 manufactured as described above can basically exhibit the same effects as the perpendicular recording magnetic heads of other examples.

(Second Embodiment)
10A to 10K are sectional views in the height direction showing the manufacturing process of the perpendicular recording magnetic head according to the second embodiment of the invention. 11A to 11F are cross-sectional views in the track width direction showing the manufacturing process of the perpendicular recording magnetic head according to the second embodiment of the invention. 12A to 12F are plan views showing the formation process of the main magnetic pole and the main magnetic pole auxiliary layer in the manufacturing process of the perpendicular recording magnetic head according to the second embodiment of the present invention.

10A to 10K, FIGS. 11A to 11F, and FIGS. 12A to 12F, the same reference numerals as those in FIGS. 1 to 3 denote the same elements.
First, as shown in FIG. 10A, a first insulating layer made of an alumina (aluminum oxide: Al ₂ O ₃ ) layer is formed on a substrate 61 made of a nonmagnetic insulating material, for example, AlTiC (Al ₂ O ₃ .TiO ₂ ). A reproducing magnetic head 90 a is formed through the layer 62.

  The reproducing magnetic head 90a includes, for example, a lower magnetic shield layer 63, a lower gap layer 64a, a reproducing element 65, an upper gap layer 64b, and an upper magnetic shield layer 66 that are sequentially formed on the first insulating layer 62. ing.

  The lower magnetic shield layer 63 and the upper magnetic shield layer 66 are each formed by sputtering, and are composed of, for example, a NiFe alloy layer containing iron (Fe) at a rate of 80 wt.% And nickel (Ni) at a rate of 20 wt.%. The lower gap layer 64a and the upper gap layer 64b are each formed by sputtering, and are made of an insulating material such as alumina.

For example, one of an MR element, a GMR element, and a TMR element is formed as the reproducing element 65. The reproducing element 65 is formed in an air bearing surface (ABS surface) of the magnetic head, that is, a region that is a medium facing surface, and is connected to a pair of electrodes (not shown).
After forming the insulating separation layer 67 made of a nonmagnetic insulating material such as alumina on the reproducing magnetic head 90a, a perpendicular recording magnetic head is formed by the following process.

  First, as shown in FIG. 10B, a first return yoke layer 68 and a first insulating layer 69 are sequentially formed on the insulating separation layer 67. As a constituent material of the first return yoke layer 68, for example, Fe is 80 wt.%. A NiFe alloy containing Ni at a rate of 20 wt.% Is used. Further, as a constituent material of the first insulating layer 69, for example, an alumina layer formed by sputtering is used.

  After that, the first conductive thin film coil 70 is formed in a region on the first insulating layer 69 that is 1 μm or more away from the portion that becomes the medium facing surface. The first conductive coil 70 is formed in a spiral shape by patterning a conductive layer such as copper formed by sputtering, plating, or the like by photolithography, lift-off, or the like. The planar shape as shown in FIG.

  Next, an organic insulating material such as polyimide or photoresist is formed on the first conductive thin film coil 70 and the first insulating layer 69, and this is patterned to cover the first conductive coil 70. A second insulating layer 71 is formed. The second insulating layer 71 is removed from the medium facing surface and its periphery during patterning.

Further, after an alumina layer is formed as the third insulating layer 72 on the first and second insulating layers 69 and 71, the upper surface thereof is polished and planarized by the CMP method.
Next, as shown in FIG. 10C, a photoresist is applied to the upper surface of the third insulating layer 72, and this is exposed and developed, so that the gap is almost at the center of the first conductive thin film coil 70. A hole forming resist pattern 73 having an opening 73a is formed.

  Further, the first, second, and third insulating layers 69, 71, and 72 are removed by the ion milling method or the sputter etching method through the opening 73a of the hole forming resist pattern 73 to form the first contact hole 72a. A part of the first return yoke layer 68 is exposed in the first contact hole 72a.

After removing the hole-forming resist pattern 73 with acetone or the like, as shown in FIG. 10D, a photoresist 74 is again applied on the third insulating layer 72, and this is exposed and developed, whereby a medium facing surface is obtained. An opening 74a is formed, for example, 0.5 μm to 1 μm away from the portion to be formed in the magnetic head height direction. The planar shape of the opening 74a is a rectangle in which the length x of two sides parallel to the medium facing surface is, for example, 10 μm or more, and the length y of two sides in the direction perpendicular to the medium facing surface is, for example, 10 μm. It has become.
The medium facing surface refers to the position of the surface that should become the medium facing surface in the future until it is actually formed.

Next, as shown in FIG. 10E, the main magnetic pole auxiliary layer 75 is formed on the fifth insulating layer 72 through the opening 74a of the resist pattern 74 by, for example, an electroless plating method or a sputtering method. The thickness of the main magnetic pole auxiliary layer 75 is set to be 0.5 μm to 2 μm, for example, 0.6 μm after polishing, which will be described later.
As the main magnetic pole auxiliary layer 75, a magnetic layer such as a cobalt nickel iron (CoFeNi) alloy layer having a saturation magnetic flux density Bs of 1.8T (Tesla) or a NiFe alloy layer having a saturation magnetic flux density Bs of 1.5T is formed. The When the main magnetic pole auxiliary layer 75 is made of CoFeNi, for example, the composition of Co is 65 wt.%, Ni is 15 wt.%, And Fe is 65 wt.%.

  After removing the resist pattern 74 with acetone or the like, the cross-sectional structure of the laminated structure from the substrate 61 to the main magnetic pole auxiliary layer 75 viewed from the medium facing surface side is as shown in FIG. 11A. The magnetic layer formed on the resist pattern 74 is peeled off by a lift-off method, that is, by removing the resist pattern 74.

Subsequently, as shown in FIG. 10F, an alumina layer or a silicon oxide (SiO ₂ ) layer is formed as a fourth insulating layer 76 on the main magnetic pole auxiliary layer 75 and the third insulating layer 72 by a sputtering method. Further, the fourth insulating layer 76 is polished by CMP to expose the upper surface of the main magnetic pole auxiliary layer 75, and the fourth insulating layer 76 and the main magnetic pole auxiliary layer 75 are planarized. In this case, the upper surface of the main magnetic pole auxiliary layer 75 is also polished to adjust the thickness.

  The polished main magnetic pole auxiliary layer 75 has a planar shape as shown in FIG. 12B and is surrounded by a fourth insulating layer 76. Further, a cross-sectional structure of the laminated structure from the substrate 61 to the fourth insulating layer 76 viewed from the medium facing surface side is as shown in FIG. 11B.

  Next, as shown in FIG. 10G, a photoresist is applied on the fourth insulating layer 76 and the main magnetic pole auxiliary layer 75, and this is exposed and developed, so that a part of the upper surface of the main magnetic pole auxiliary layer 75 is formed. A resist pattern 77 having a main magnetic pole shape having an overlapping opening 77a is formed.

  As shown in FIG. 12C, the opening 77a of the resist pattern 77 has a rectangular first region 77b that overlaps the main magnetic pole auxiliary layer 75 and a tapered shape that protrudes from a part of the edge of the first region 77b on the medium facing surface side. The second region 77c and a third region 77d in a linear stripe shape projecting from the second region 77c to the portion that becomes the medium facing surface. A part of the second region 77c overlaps the main magnetic pole auxiliary layer 75, and the third region 77d has a substantially uniform width.

  Subsequently, as shown in FIG. 10H, the main magnetic pole layer 78 is electrolessly plated on the main magnetic pole auxiliary layer 75 and a part of the sixth insulating layer 76 through the opening 77a of the main magnetic pole forming resist pattern 77. Formed by sputtering or sputtering. The main magnetic pole layer 78 is formed to have a thickness of about 0.1 μm to 0.3 μm, for example, 0.2 μm, which is thinner than the main magnetic pole auxiliary layer 75 after polishing, which will be described later.

  As the main magnetic pole layer 78, for example, a magnetic layer having a saturation magnetic flux density Bs larger than the saturation magnetic flux density Bs of the main magnetic pole auxiliary layer 75, for example, a FeNi alloy layer having Bs of 2.1T or a CoFe alloy layer having Bs of 2.3T is formed. To do. When the main magnetic pole layer 78 is made of FeNi, for example, the composition of Fe is 90 wt.% And Ni is 10 wt.%.

    As shown in FIG. 12D, the main magnetic pole layer 78 after the main magnetic pole forming resist pattern 77 is removed includes a rectangular yoke portion 78a that overlaps the main magnetic pole auxiliary layer 75, and an edge on the medium facing surface side of the yoke portion 78a. And a tapered portion 78b protruding from the leading end 78c extending from the narrow tip of the restricting portion 78b to the medium facing surface. By removing the main magnetic pole forming resist pattern 77 with acetone or the like, the magnetic layer in the region excluding the opening 77a is peeled off.

  The yoke portion 78a, the restricting portion 78b, and the tip portion 78c are magnetically coupled, and the tip portion 78c is formed in a linear stripe shape having a substantially uniform width and serves as a magnetic flux saturation position of the main magnetic pole layer 78. Yes. In this case, a part of the main magnetic pole auxiliary layer 75 protrudes from the yoke part 78a to a part of the narrowed part 78b, and unlike the main magnetic pole layer 75, it is not exposed from the medium facing surface.

The width of the yoke portion 78a side of the portion 78b is for example 10μm or less, the core width _{w c} of the tip portion 78c is 0.1μm, for example.
The formation methods of the main magnetic pole 78 and the main magnetic pole auxiliary layer 75 are not limited to the electroless plating method and the sputtering method, respectively, and an electrolytic plating method and other methods may be adopted.

For example, when the main magnetic pole layer 78 is formed by the electrolytic plating method, a resist film having an opening similar to that shown in the first embodiment may be used. Alternatively, after the magnetic layer is formed on the entire surface of the main magnetic pole auxiliary layer 75 and the sixth insulating layer 76, the magnetic material layer is patterned by photolithography to form the main magnetic pole 78 or the main magnetic pole auxiliary layer 75. Good.
FIG. 11C shows a cross section of the laminated structure from the main magnetic pole layer 78 to the substrate 61 formed by such a method as viewed from the medium facing surface side.

  Next, as shown in FIG. 11D, at least the front end portion 78c of the main magnetic pole layer 78 is subjected to ion milling or reactive ion etching (RIE) on both sides in the core width direction in an oblique direction, thereby both sides thereof. A ridge-like taper surface is formed at the edge of the ridge. As a result, the cross section of the tip 78c of the main pole 78 has a trapezoidal shape. The trapezoidal shape here is the same shape as the inverted trapezoidal shape in the first embodiment, and has a shape in which the bottom side on the trailing side is longer than the bottom side on the leading side of the magnetic head.

  In order to prevent the main magnetic pole 78 from being thinned by ion milling, the upper surface of the main magnetic pole 78 may be covered with a mask of photoresist, alumina or the like before ion milling.

  Subsequently, as shown in FIG. 10I, an alumina layer or a silicon oxide layer is formed as a fifth insulating layer 79 on the main magnetic pole layer 78 and the sixth insulating layer 76 by a sputtering method. Subsequently, the fifth insulating layer 79 is polished by CMP to expose the upper surface of the main magnetic pole layer 78, and the fifth insulating layer 79 and the main magnetic pole layer 78 are planarized. The polished main magnetic pole layer 78 is surrounded by the seventh insulating layer 76. In this case, the upper surface of the main magnetic pole layer 78 is also polished to adjust the thickness.

  Next, as shown in FIGS. 10J and 11E, a gap layer 80 made of alumina is formed on the main magnetic pole 78 and the fifth insulating layer 79 by sputtering, and then a spiral second conductive material made of copper is formed. The conductive thin film coil 81 is formed on the gap layer 80, and the sixth insulating layer 82 made of an organic material or the like is formed on the second conductive thin film coil 81 and the gap layer 80.

As shown in the plan view of FIG. 12E, the second conductive thin film coil 81 is formed at a position where a part thereof overlaps above the yoke portion 78 a of the main magnetic pole 78.
After patterning the sixth insulating layer 82 into a predetermined shape, a seventh insulating layer 83 made of alumina, for example, is formed on the gap layer 80 and the sixth insulating layer 82, and the surface of the seventh insulating layer 83 is further formed. Is planarized by CMP.

In addition, the formation method of each layer from the gap layer 80 to the 7th insulating layer 83 employ | adopts the same method as the process of forming from the 1st insulating layer 69 to the 3rd insulating layer 72 mentioned above.
Next, steps required until a structure shown in FIGS. 10K and 12F is formed will be described.

  First, the sixth and seventh insulating layers 82 and 83 and the gap layer 80 are patterned by photolithography, so that the first contact hole 73a passes through the gap at the substantially central position of the second conductive thin film coil 82. A second contact hole 83 is formed at a position overlapping with the second contact hole 83. As a result, a part of the yoke portion 78 a of the main magnetic pole layer 78 is exposed in the second contact hole 83.

Next, a second return yoke layer 84 is formed by sputtering in the second contact hole 83 and on the seventh insulating layer 83. The second return yoke layer 84 is formed using, for example, the same material as the first return yoke layer 68, and is patterned by a lift-off method or a photolithography method.
The second return yoke layer 84 is formed in a region that overlaps at least the main magnetic pole auxiliary layer 75 and includes the second contact hole 83a, and is further removed from the shield region on the medium facing surface side.

Accordingly, the second return yoke layer 84 is magnetically and structurally connected to the main magnetic pole 78, the main magnetic pole auxiliary layer 75, and the first return yoke layer 68 through the first and second contact holes 73a and 83a. Is done.
Next, the seventh insulating layer 83 is patterned by photolithography to be removed from the medium facing surface and the surrounding shield region, and the gap layer 80 is exposed. A write shield portion 85 connected to the second return yoke layer 84 is formed on the gap layer 80 in the shield region by a lift-off method or the like.

As a magnetic material constituting the write shield portion 85, for example, a CoFeNi alloy layer having a saturation magnetic flux density Bs equivalent to 1.8T is formed. CoFeNi is formed to have a content of, for example, 65 wt.% Co, 15 wt.% Ni, and 65 wt.% Fe.
After that, after the substrate 1 is cut into a predetermined shape and polished, the region including the tip 78c of the main pole 78 is polished as shown in FIG. 11F, and the polished surface becomes the medium facing surface 86. The substrate 1 is shaped and finally becomes the slider 13 shown in FIG.

  The perpendicular recording magnetic head 90b is configured by the layer structure from the first return yoke layer 68 to the second return yoke layer 84 as described above. The perpendicular recording / reproducing magnetic head 90b constitutes a perpendicular recording / reproducing magnetic head 90 together with the reproducing magnetic head 90a, and the perpendicular recording / reproducing magnetic head 90 is used as the magnetic head element section 14 on the slider 13 shown in FIG. The

The term perpendicular recording / reproducing head is also used as a concept including both the reproducing magnetic head and the recording magnetic head.
The perpendicular recording / reproducing magnetic head 90 formed by the processes as described above can be performed using an existing microfabrication technique, and the manufacturing method thereof is easy, so that the number of processes does not increase as compared with the prior art. The gap layer 80 may be composed of a nonmagnetic layer such as Ru, but in order to prevent connection with the second conductive thin film coil 81, it is necessary to form an insulating film therebetween. There is.

The perpendicular recording magnetic head 90b is arranged so that the first return yoke layer 68 is on the leading side and the second return yoke layer 84 is on the trailing side with the medium facing surface 86 facing the magnetic recording medium. Is done.
When the first and second conductive thin film coils 70 and 81 of the perpendicular recording magnetic head 90 are excited by flowing current, as shown in FIG. 13, the end face of the tip 78c of the main magnetic pole layer 78 and the soft magnetic backing layer. A magnetic field A in the vertical direction is generated between 32, whereby the recording layer 33 of the perpendicular recording medium 15 is magnetized in the vertical direction and magnetic information is recorded. The perpendicular recording magnetic head 90 shown in FIG. 13 is drawn with the substrate and the insulating layer omitted.

The magnetic field A passing through the tip 78c of the main magnetic pole layer 78 and the recording layer 33 circulates in the backing layer 32 to form one magnetic circuit that returns to the first and second return yoke layers 68 and 84.
As shown in FIGS. 14A and 14B, the main magnetic pole auxiliary layer 75 below the main magnetic pole layer 78 has a quadrangular shape in which the wings are expanded in the track width t ₀ direction. It is formed below the portion 78a and protrudes from a part of the narrowed portion 78b. As a result, the area of the planar shape of the main magnetic pole auxiliary layer 75 is wider than that of the yoke portion 78 a of the main magnetic pole 78.

  When comparing the edges 75e and 78e on the medium facing surface 85 side of the yoke portion 78a of the main magnetic pole layer 78 and the main magnetic pole auxiliary layer 75, the first edge 75e of the main magnetic pole auxiliary layer 75 is the edge 78e of the yoke portion 78a. Rather closer to the medium facing surface. The edge of the yoke part 78a overlaps with the throttle part 78b, but does not reach the root of the tip part 78c.

  By forming the main magnetic pole auxiliary layer 75 and the main magnetic pole layer 78 in such a structure, the magnetic field generated on the medium facing surface of the tip 78c of the main magnetic pole layer 78 is increased as compared with the conventional perpendicular recording magnetic head. In addition, since the position where the magnetic pole saturation of the main magnetic pole layer 78 occurs is close to the medium facing surface 75, an unnecessary leakage magnetic field to the periphery of the tip 78c of the main magnetic pole layer 78 can be greatly suppressed. As a result, the possibility of rewriting the magnetic information recorded in the adjacent track adjacent to the write position of the tip 78c of the main magnetic pole layer 78 is lower than in the prior art.

  The perpendicular recording magnetic head of this embodiment having the main magnetic pole layer 78 and the main magnetic pole auxiliary layer 75 shown in FIGS. 14A and 14B, and the perpendicular recording having the conventional main magnetic pole 100 and the main magnetic pole auxiliary layer 111 shown in FIG. For each of the magnetic heads, the relationship between the distance (position) h from the medium facing surface to the nearest edge of the main magnetic pole auxiliary layers 75 and 111 and the recording magnetic field was simulated, and the results shown in FIG. 15 were obtained. The recording magnetic field is a magnetic field passing through the medium facing surface of the main magnetic pole tips 78c and 100c necessary for recording magnetic information on the recording layer 33, and the magnitude when the magnetomotive force (MMF) is 0.2AT. It is shown in

A conventional recording magnetic head has a main magnetic pole 100 composed of a yoke part 100a, a diaphragm part 100b, and a tip part 100c, and the planar shape excluding the tip part 100c is substantially pentagonal. Further, the conventional main magnetic pole auxiliary layer is formed so as to overlap only with the yoke portion 100a.
In this case, the thickness of the main magnetic pole auxiliary layers 75 and 111 is 0.6 μm, the thickness of the main magnetic poles 78 and 100 is 0.2 μm, and the recorded track width t _c is 0.12 μm.

The change in the distance h between the main magnetic pole auxiliary layers 75 and 111 is accompanied by a change in the lengths of the tip portions 78c and 100c of the main magnetic pole layers 78 and 100.
In FIG. 15, there was almost no difference in the characteristics of the recording magnetic head of this embodiment and the conventional magnetic head. The recording magnetic field increases as the main magnetic pole auxiliary layers 75 and 111 are brought closer to the medium facing surface. When the distance is reduced from 2 μm to 1 μm, the recording magnetic field increases by about 4%.

  Next, for each of the perpendicular recording magnetic head according to the present embodiment and the conventional perpendicular recording magnetic head, the relationship between the distance (position) h of the main pole auxiliary layers 75 and 111 from the medium facing surface and the adjacent erase magnetic field was simulated. However, the results shown in FIG. 16 were obtained. The adjacent erase magnetic field is a magnetic field applied to the track adjacent to the tip of the main magnetic pole, and is shown in the magnitude when the magnetomotive force is 0.2 AT.

  When the recording magnetic head having the main magnetic pole layer 100 and the main magnetic pole auxiliary layer 111 having the conventional structure is used, as shown by the broken line in FIG. 16, the distance h between the main magnetic pole auxiliary layer and the medium facing surface becomes closer to the adjacent track. The strength of such a magnetic field tends to increase. This is related to the magnetic flux saturation of the main magnetic pole 100, and it is considered that an unnecessary magnetic field, that is, a leakage magnetic field is generated and spreads from the front end portion 100c of the main magnetic pole 100 as the magnetic field required for information recording increases. It is done.

  On the other hand, when the recording magnetic head of the present embodiment in which the main magnetic pole auxiliary layer 75 is protruded halfway through the narrowed portion 78b of the main magnetic pole layer 78, as shown by the solid line in FIG. Even when approaching from 1 to 1 μm, the intensity of the magnetic field applied to the adjacent track hardly changed or tended to decrease slightly. This is presumably because magnetic flux saturation at the tip 78c of the main magnetic pole layer 78 is suppressed by employing the main magnetic pole layer 78 and the main magnetic pole auxiliary layer 75 shown in FIG.

  From the above, by causing the main magnetic pole auxiliary layer 75 joined to the yoke portion 78a of the main magnetic pole layer 78 and magnetically coupled to protrude toward the medium facing surface side, the magnetic flux saturation is suppressed and the adjacent erase magnetic field is generated. It can be seen that, at the same time, the vertical component of the recording magnetic field passing through the tip 78c of the main magnetic pole layer 78 can be increased.

  In particular, suppression of the adjacent erase magnetic field is important in consideration of further increase in recording density of the magnetic disk device. In this case, when the distance of the main magnetic pole auxiliary layer 75 relative to the medium facing surface is 2 μm or less and is in the range of 0.1 μm or more, the effect of suppressing the increase of the erase magnetic field appears remarkably. In consideration of the core length, 0.5 μm or more is preferable.

By providing the main magnetic pole auxiliary layer 75 according to the present embodiment at such a position, the recording magnetic field can be increased by 6% or more than before without changing the adjacent erase magnetic field, which is suitable for increasing the recording density. It is possible to provide a perpendicular recording magnetic head.
The planar shape of the region where the main magnetic pole auxiliary layer 75 protrudes from the yoke portion 78a of the main magnetic pole layer 78 toward the medium facing surface does not necessarily have to be a quadrangle as shown in FIGS. 14A and 14B. For example, as shown in the plan views of FIGS. 17A and 17B, the main magnetic pole auxiliary layer 75 needs to protrude from a part of the narrowed portion 78b of the main magnetic pole layer 78 in the track width direction.

  On the other hand, as shown in the reference of the plan view and side view of FIGS. 18A and 18B, when the planar shape of the main magnetic pole auxiliary layer 75a is made to coincide with the yoke portion 78a and the throttle portion 78b, FIGS. As shown by the broken line, not only the recording magnetic field but also the erasing magnetic field increases as the distance h from the medium facing surface decreases, so it is not suitable for increasing the recording density.

Note that the solid lines in FIGS. 19 and 20 show the characteristics of the present embodiment shown by the solid lines in FIGS. 18 and 19 for comparison.
By the way, as shown in the plan view and the end view of FIGS. 21A and 21B, the regions 75b and 75c on both sides of the narrowed portion 78b of the main magnetic pole layer 78 in the main magnetic pole auxiliary layer 75 are less saturated than the central region. You may comprise from the material used as magnetic flux density. As a result, the magnetic flux of the main magnetic pole auxiliary layer 75 can be collected in the central region, and the recording magnetic field passing through the tip 78c of the main magnetic pole layer 78 can be increased.

(Third embodiment)
22A and 22B are a plan view and a side view showing the main magnetic pole layer and the main magnetic pole auxiliary layer of the perpendicular recording magnetic head according to the third embodiment of the present invention. 22A and 22B, the same reference numerals as those in FIGS. 14A and 14B indicate the same elements.

  22A and 22B, the main magnetic pole layer 91 and the main magnetic pole auxiliary layer 75 constituting the perpendicular recording magnetic head have the same shape and position as the main magnetic pole layer 78 and the main magnetic pole auxiliary layer 75 shown in the second embodiment, respectively. It is formed. As shown in FIG. 10K, first and second conductive thin film coils 70 and 81 are formed at an interval above and below the first and second return yoke layers 68 and 81 above and below them. 84 is formed.

  The main magnetic pole auxiliary layer 75 is joined and magnetically coupled to one surface of the yoke portion 91a of the main magnetic pole layer 91, and the edge on the medium facing surface side of the main magnetic pole auxiliary layer 75 is narrowed from the yoke portion 91a. It protrudes to the medium facing surface side up to the portion 91b and has a size overlapping with a part of the throttle portion 91b.

  The tip 91c of the main magnetic pole layer 91 as viewed from the medium facing surface has a trapezoidal shape in which the bottom on the trailing side is wider than the bottom on the leading side, as shown in FIG. 23A. In addition, the saturation magnetic flux density of the main magnetic pole layer 91 including the tip 91 decreases continuously or stepwise from the trailing edge toward the leading edge, as in the first embodiment.

  For example, as shown in FIG. 23A, a plurality of magnetic layers 91A, 91B, and 91C having different saturation magnetic flux densities are formed in order of decreasing saturation magnetic flux density from the leading edge to the trailing edge. In this case, as shown in FIG. 23B, a nonmagnetic layer 92 such as Ru may be interposed between the plurality of magnetic layers 91A, 91B, 91C.

  That is, the main magnetic pole layer 91 is laminated with a magnetic material selected so that the saturation magnetic flux density Bs increases continuously or stepwise in the film thickness direction from the leading side to the trailing side. It has a gradient.

  For example, when the saturation magnetic flux density Bs changes stepwise as shown in FIG. 23A, the main magnetic pole layer 91 is composed of a laminated film of three materials having at least different saturation magnetic flux densities Bs. The first magnetic layer 91A, which is the uppermost layer on the trailing side, is made of a magnetic material having a saturation magnetic flux density Bs of 2.0 T or more, and the third magnetic layer 91C, which is the lowermost layer on the leading side, is 1.0 T. It is preferable that the second magnetic layer 91B between them is made of the following magnetic material, and the intermediate magnetic material is used. The ratio of the saturation magnetic flux density Bs of the first magnetic layer 91A to the third magnetic layer 91C is desirably 2.0 or more.

As described above, the main magnetic pole layer 91 having a different saturation magnetic flux density in the thickness direction, and the planar rectangular main magnetic pole auxiliary layer 75 formed at a position overlapping the yoke portion 91a of the main magnetic pole layer 91 and a part of the throttle portion 91b. When the relationship between the distance h of the main magnetic pole auxiliary layer 75 from the medium facing surface and the recording magnetic field was obtained, the characteristics shown by the solid line in FIG. 24 were obtained. In this case, the thickness of the main magnetic pole auxiliary layer 75 is 0.6 μm, the thickness of the main magnetic pole 91 is 0.2 μm, and the recorded track width t _c is 0.12 μm. The distance between the yoke portion 91a of the main magnetic pole layer 91 and the medium facing surface is longer than the distance between the main magnetic pole auxiliary layer 75 and the medium facing surface.

  According to the solid line in FIG. 24, the recording magnetic field increases as the position of the main magnetic pole auxiliary layer 75 approaches the medium facing surface. When the distance is reduced from 2 μm to 1 μm, the recording magnetic field required for writing increases by about 4%. Further, when the distance is reduced from 1 μm to 0.3 μm, it further increases by about 6%. However, considering the length of the tip 91c of the main magnetic pole layer 91, the distance is preferably 0.5 μm or more.

  On the other hand, the recording magnetic field characteristic of the perpendicular recording magnetic head according to the second embodiment having the main magnetic pole layer 78 in which the saturation magnetic flux density is uniformly distributed in the thickness direction is as shown by the broken line in FIG. In the configuration, the recording magnetic field can be slightly increased as compared with the second embodiment.

Next, for the recording magnetic head according to the present embodiment, the relationship between the distance h between the medium facing surface and the main magnetic pole auxiliary layer 75 and the adjacent erase magnetic field was obtained, and the result shown by the solid line in FIG. 25 was obtained. The value of the adjacent erase magnetic field in this case is the magnitude when the magnetomotive force is 0.2 AT. The main magnetic pole auxiliary layer 75 has a thickness of 0.6 μm, the main magnetic pole 78 has a thickness of 0.2 μm, and the recorded track width t _c is 0.12 μm.

  According to the solid line in FIG. 25, in the perpendicular recording magnetic head, when the distance from the medium facing surface to the main magnetic pole auxiliary layer is reduced from 2 μm to 0.3 μm, the intensity of the adjacent erase magnetic field applied to the adjacent track is reduced by about 7%. did.

  On the other hand, the adjacent erase magnetic field characteristic of the perpendicular recording magnetic head according to the second embodiment having the main magnetic pole layer 78 in which the saturation magnetic flux density is uniformly distributed is as shown by the broken line in FIG. The magnetic field characteristics are slightly smaller than the adjacent erase magnetic field characteristics of the second embodiment.

  This is because in the main magnetic pole layer 91 used in the present embodiment, recording is performed with a large magnetic field at the trailing edge of the main magnetic pole layer 91 due to a change in the saturation magnetic flux density in the film thickness direction. This is because the spread of the magnetic field due to the protrusion of the tip 91c of the main magnetic pole layer 91 from the track is further suppressed than in the second embodiment.

From the above, the main magnetic pole layer 91 having a different saturation magnetic flux density distribution in the thickness direction and the main magnetic pole auxiliary layer 75 extending from the bottom of the yoke portion 91a of the main magnetic pole layer 91 to a part of the throttle portion 91b. According to the perpendicular recording magnetic head, the generation of the erase magnetic field on the adjacent track can be suppressed more than before, and the magnetic field required for recording can be increased more than before.
In the present embodiment, the main magnetic pole layer 91 may employ the structure described in the first embodiment, and the main magnetic pole auxiliary layer 75 may be described in the second embodiment. A structure may be adopted.

Below, the characteristic of embodiment which concerns on this invention is added.
(Supplementary Note 1) A first magnetic pole having a recording magnetic field output surface that has a trapezoidal shape with a bottom on the trailing side that is longer than the bottom on the leading side and has a smaller saturation magnetic flux density distribution from the trailing side toward the leading side. A perpendicular recording magnetic head comprising:
(Supplementary note 2) The perpendicular recording magnetic head according to supplementary note 1, wherein the first magnetic pole is made of at least three magnetic materials having different saturation magnetic flux densities.
(Appendix 3) The three magnetic materials are composed of a first magnetic material having a saturation magnetic flux density of 2.0 T or more on the trailing side and a second magnetic material having a saturation magnetic flux density of 1.0 T or less on the leading side. The perpendicular recording magnetic head according to appendix 2, wherein a ratio of the saturation magnetic flux density of the first magnetic material to the saturation magnetic flux density of the second magnetic material is 2.0 or more.
(Supplementary note 4) The perpendicular recording magnetic head according to supplementary note 2, wherein the three magnetic materials are composed of multilayer films having different saturation magnetic flux densities formed through a nonmagnetic material layer.
(Supplementary note 5) The perpendicular recording magnetic head according to any one of Supplementary notes 1 to 4, further comprising a second magnetic pole magnetically coupled to a part of the first magnetic pole.
(Appendix 6) A perpendicular recording magnetic head mounted on a slider having a medium facing surface,
A planar first magnetic pole magnetically coupled in the order of the tip portion, the aperture portion, and the yoke portion from the medium facing surface, wherein the tip portion includes a recording core;
The second magnetic pole is magnetically coupled to at least the yoke portion of the first magnetic pole, and the planar shape is formed such that the length in the core width direction is longer than the length in the direction perpendicular to the core width direction of the recording core. A perpendicular recording magnetic head comprising a magnetic pole.
(Supplementary note 7) The supplementary note 6 is characterized in that an edge on the medium facing surface side of the second magnetic pole is closer to the medium facing surface than an edge on the medium facing surface side in the yoke portion of the first magnetic pole. The perpendicular recording magnetic head described.
(Appendix 8) The perpendicular recording magnetic head according to appendix 7, wherein an edge of the second magnetic pole on the medium facing surface side is not exposed to the medium facing surface.
(Appendix 9) The appendix 6 to appendix 8, wherein the second magnetic pole is magnetically coupled only to part of the yoke portion and the throttle portion of the first magnetic pole. Perpendicular magnetic recording head.
(Supplementary Note 10) Any one of Supplementary Notes 6 to 8, wherein a portion of the second magnetic pole that is magnetically coupled to the yoke portion is wider in the core width direction than the first magnetic pole. A perpendicular recording magnetic head according to claim 1.
(Supplementary Note 11) The perpendicular recording magnetic head according to any one of Supplementary Notes 6 to 10, wherein the planar shape of the second magnetic pole is the same as the planar shape of the yoke portion of the first magnetic pole.
(Supplementary note 12) The perpendicular recording magnetic head according to any one of Supplementary notes 6 to 10, wherein the planar shape of the second magnetic pole is rectangular.
(Additional remark 13) The saturation magnetic flux density of the magnetic material which comprises the said 1st magnetic pole is larger than the saturation magnetic flux density of the magnetic material which comprises the said 2nd magnetic pole, The additional remark 6 thru | or the additional remark 12 characterized by the above-mentioned Perpendicular recording magnetic head.
(Supplementary Note 14) The vertical according to any one of Supplementary Notes 6 to 13, wherein the magnetic material constituting the second magnetic pole is thicker than the magnetic material constituting the first magnetic pole. Recording magnetic head.
(Supplementary note 15) In the second magnetic pole, two regions on both sides of the narrowed portion are made of a magnetic material having a lower saturation magnetic flux density than a region sandwiched between the two regions. 15. The perpendicular recording magnetic head according to any one of 6 to appendix 14.
(Supplementary Note 16) The perpendicular recording magnetic head according to any one of Supplementary Notes 6 to 15, wherein a distance between the second magnetic pole and the medium facing surface is in a range of 0.5 μm to 2.0 μm.
(Supplementary note 17) A perpendicular recording magnetic head mounted on a slider having a medium facing surface,
A first magnetic pole that is magnetically coupled in order from the medium facing surface to the tip portion, the throttle portion, and the yoke portion, and whose saturation magnetic flux density decreases from the trailing side toward the leading side;
The second magnetic pole is magnetically coupled to at least the yoke portion of the first magnetic pole, and the planar shape is formed to be longer in the core width direction than in the direction perpendicular to the core width direction of the recording core. A perpendicular recording magnetic head comprising a magnetic pole.
(Supplementary note 18) The perpendicular recording magnetic head according to supplementary note 17, wherein the first magnetic pole has a trapezoidal shape in which the bottom side on the trailing side is longer than the bottom side on the leading side.
(Supplementary note 19) The supplementary note 17 or 18, wherein an edge on the medium facing surface side of the second magnetic pole is closer to the medium facing surface than an edge on the medium facing surface side of the yoke portion of the first magnetic pole. The perpendicular recording magnetic head according to appendix 18.
(Supplementary note 20) The perpendicular magnetism according to any one of supplementary notes 17 to 19, wherein the second magnetic pole is magnetically coupled only to a part of the yoke portion and the throttle portion of the first magnetic pole. Recording head.
(Supplementary Note 21) A third magnetic pole having an end face adjacent to the medium facing surface side of the first magnetic pole via a gap and magnetically coupled to the first magnetic pole;
The perpendicular recording magnetic head according to any one of appendices 1 to 20, further comprising a magnetic field generation source that generates a recording magnetic field passing through the first magnetic pole and the third magnetic pole.
(Appendix 22) The perpendicular recording magnetic head according to any one of claims 1 to 21,
A magnetic disk device comprising at least a magnetic disk facing the perpendicular magnetic head.

FIG. 1 is a plan view showing an example of the inside of a magnetic disk apparatus equipped with a perpendicular recording magnetic head according to an embodiment of the present invention. FIG. 2 is an explanatory view of the main part showing the flow of magnetic flux between the magnetic head and the magnetic disk in the recording process of perpendicular recording. 3A and 3B are a front view and a side view of the main part showing the overall configuration of the perpendicular magnetic recording head according to the first embodiment of the present invention. 4A, 4B, and 4C are enlarged explanatory views of main portions of the main magnetic pole and the vicinity thereof in the perpendicular recording magnetic head according to the first embodiment of the present invention. FIG. 5A is a plan view of the main part showing the main magnetic pole constituting the perpendicular recording magnetic head according to the first embodiment of the present invention as viewed from the air bearing surface, and FIG. 5B constitutes the perpendicular recording magnetic head according to the prior art. It is the principal part top view which looked at the main pole, and represented it from the air bearing surface. 6A and 6B are diagrams showing two-dimensional head magnetic field distributions showing simulation results performed for the main magnetic poles shown in FIGS. 5A and 5B. FIG. 7 is a diagram showing the head magnetic field distribution in the down-track direction at the track center of the magnetic disk by comparing the main magnetic pole according to the present invention (solid line) with the main magnetic pole according to the prior art (broken line). . FIG. 8A to FIG. 8C are main part cut side views (part 1) showing the main pole in the process key points for explaining Example 1 of the process of manufacturing the main pole according to the present invention. FIG. 8D and FIG. 8E are main part cut side views (No. 2) showing the main pole in the process key points for explaining Example 1 of the process of manufacturing the main pole according to the present invention. 9A to 9D are cutaway side views of the main part showing the main magnetic pole in process points for explaining Example 2 of the process of manufacturing the main magnetic pole according to the present invention. 10A to 10C are side sectional views (No. 1) showing the manufacturing process of the magnetic head according to the second embodiment of the invention. 10D to 10F are side sectional views (No. 2) showing the manufacturing process of the magnetic head according to the second embodiment of the invention. 10G to 10I are side sectional views (No. 3) showing the manufacturing process of the magnetic head according to the second embodiment of the invention. 10J to 10K are side sectional views (No. 4) showing the manufacturing process of the magnetic head according to the second embodiment of the invention. 11A to 11C are cross-sectional views (No. 1) viewed from the medium facing surface side showing the manufacturing process of the magnetic head according to the second embodiment of the invention. 11D to 11F are sectional views (No. 2) seen from the medium facing surface side showing the manufacturing process of the magnetic head according to the second embodiment of the invention. 12A to 12C are plan views (part 1) illustrating the manufacturing process of the magnetic head according to the second embodiment of the invention. 12D to 12F are plan views (part 2) illustrating the manufacturing process of the magnetic head according to the second embodiment of the invention. FIG. 13 is a side view of the main part showing the positional relationship between the perpendicular magnetic recording head and the magnetic recording medium according to the second embodiment of the present invention. 14A and 14B are a front view and a side view, respectively, showing the positional relationship between the main magnetic pole and the main magnetic pole auxiliary layer constituting the perpendicular magnetic recording head according to the second embodiment of the present invention with respect to the magnetic recording medium. FIG. 15 is a diagram showing the relationship between the recording magnetic field and the distance from the medium facing surface of the main magnetic pole auxiliary layer constituting the perpendicular magnetic recording head according to the second embodiment of the present invention and the prior art. FIG. 16 is a diagram showing the relationship between the distance from the medium facing surface and the adjacent erase magnetic field of the main magnetic pole auxiliary layer constituting the perpendicular magnetic recording head according to the second embodiment of the present invention and the prior art. FIG. 17A and FIG. 17B are plan views showing other examples of the main magnetic pole layer and the main magnetic pole auxiliary layer constituting the perpendicular magnetic recording head according to the second embodiment of the present invention. 18A and 18B are a plan view and a side view showing the positional relationship of the main magnetic pole and the main magnetic pole auxiliary layer with respect to the magnetic recording medium in the perpendicular magnetic recording head according to the reference. FIG. 19 is a diagram showing a relationship between the distance from the medium facing surface of the main magnetic pole auxiliary layer constituting the perpendicular magnetic recording head according to the second embodiment of the present invention and the reference, and the recording magnetic field. FIG. 20 is a diagram showing the relationship between the distance from the medium facing surface of the main magnetic pole auxiliary layer constituting the perpendicular magnetic recording head according to the second embodiment of the present invention and the reference and the adjacent erase magnetic field. 21A and 21B are a plan view and a side view showing the positional relationship between the main magnetic pole and the main magnetic pole auxiliary layer constituting the perpendicular magnetic recording head according to the reference with respect to the magnetic recording medium. 22A and 22B are a plan view and a side view showing a main magnetic pole and a main magnetic pole auxiliary layer constituting a perpendicular magnetic recording head according to a third embodiment of the present invention, respectively. FIG. 23A and FIG. 23B are main part plan views showing the main pole constituting the perpendicular recording magnetic head according to the third embodiment of the present invention as seen from the air bearing surface. FIG. 24 is a diagram showing the relationship between the distance from the medium facing surface of the main magnetic pole auxiliary layer constituting the perpendicular magnetic recording head according to each of the second and third embodiments of the present invention and the recording magnetic field. FIG. 25 is a diagram showing the relationship between the distance from the medium facing surface of the main magnetic pole auxiliary layer constituting the perpendicular magnetic recording head according to each of the second and third embodiments of the present invention and the adjacent erase magnetic field. FIG. 26 is a plan view showing a main pole constituting a conventional perpendicular magnetic recording head. FIG. 27 is a waist section plan view showing the relationship between the main pole of the magnetic head and the recording surface of the magnetic disk.

Explanation of symbols

21 Main magnetic pole 22 Auxiliary magnetic pole 23 Coil 24 Write shield 27 Perpendicular recording magnetic head 75 Main magnetic pole auxiliary layer 78 Main magnetic pole layer 78a Yoke part 78b Restriction part 78c Connection part 91 Main magnetic pole layer 92a Yoke part 92b Restriction part 92c Connection part 90a Reproduction magnetism Head 90b Perpendicular recording magnetic head

Claims (6)

  It has a first magnetic pole having a recording magnetic field output surface that has a trapezoidal shape with a bottom on the trailing side that is longer than the bottom on the leading side and has a small saturation magnetic flux density distribution from the trailing side toward the leading side. A perpendicular recording magnetic head.   2. The perpendicular recording magnetic head according to claim 1, wherein the first magnetic pole is made of at least three magnetic materials having different saturation magnetic flux densities.   The three magnetic materials include a first magnetic material having a saturation magnetic flux density of 2.0 T or more on the trailing side, and a second magnetic material having a saturation magnetic flux density of 1.0 T or less on the leading side. 3. The perpendicular recording magnetic head according to claim 2, wherein a ratio of the saturation magnetic flux density of the first magnetic material to the saturation magnetic flux density of the magnetic material is 2.0 or more.   3. The perpendicular recording magnetic head according to claim 2, wherein the three magnetic materials are composed of multilayer films having different saturation magnetic flux densities formed through nonmagnetic material layers.   5. The perpendicular recording magnetic head according to claim 1, further comprising a second magnetic pole that is magnetically coupled to a part of the first magnetic pole. A perpendicular recording magnetic head according to any one of claims 1 to 5,
A magnetic disk drive comprising a magnetic disk facing the perpendicular magnetic head.

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