JP2001101625A - Magneto-resistive head and magnetic reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-resistive head of a SV head type and a magnetic reproducing device which permit a higher output by mounting an SV element having a free magnetization layer which has low magnetic resistance, high sensitivity and high efficiency. SOLUTION: The free magnetization layer of the SV head is divided into a central part and an end part (side part) according to the product of Ms.t and the product of Ms.t of the end part is made larger than that of the central part. In order to increase the product of Ms.t of the end part, it is effective to make Ms of a soft magnetic layer used in the free magnetization layer higher or to increase the film thickness. Thereby, a signal magnetic field is efficiently guided from the end part into the central part and, even when the film thickness of the free magnetization layer is made thinner for the sensitization, the signal magnetic field can be introduced thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetoresistive head and a magnetic reproducing apparatus. More specifically, the present invention relates to a magnetoresistive head with improved efficiency and higher output by improving magnetic coupling between a magnetic yoke and a magnetoresistive element, and a magnetic reproducing apparatus using the same.

[0002]

2. Description of the Related Art In recent years, the recording density of magnetic recording has been increasing.
In HDDs (hard disc drives), systems with a high recording density exceeding several Gbpsi have been put to practical use, and further higher recording densities are required. In such a high recording density magnetic recording / reproducing system, the reproducing head is
A “magnetoresistive head (hereinafter, referred to as an“ MR head ”), which utilizes a magnetoresistive effect in which the electrical resistance of a certain magnetic film changes due to an external magnetic field, has attracted attention. Among them, a "spin-valve magnetoresistive effect head (hereinafter, referred to as" SV head ") equipped with a" spin-valve magnetoresistive effect element (hereinafter, referred to as "SV element") "exhibits a particularly large magnetoresistive effect. ) Is proposed.

An SV element has at least one or more magnetization-fixed layers (pin layers), a magnetization free layer (free layer) in which magnetization can move freely, and a non-magnetic intermediate layer (spacer layer) sandwiched therebetween. ).

Hereinafter, four types of structures will be described as typical examples of the conventional SV head.

First, FIGS. 13 and 14 are perspective views conceptually showing the structure of a conventional shield type SV head. That is, the head 100A shown in FIG. 13 is a so-called "horizontal" SV head, and the head 1A shown in FIG.
00B is a so-called “vertical” SV head.

[0006] Each of the SV heads has an SV element section 102.
And a pair of electrodes 103, 103a, 103b provided at both ends thereof for supplying a sense current, and shield portions 105 provided on both sides of the SV element portion 102 in the linear recording density direction. The recording medium 200 is disposed below the head as shown in the figure, and is relatively movable between the recording medium 200 and the head.

The sense current is represented by arrow C, and
The direction of pinning of the pinned layer of the element 102 is indicated by an arrow P.

Next, FIGS. 15 and 16 are perspective views showing a schematic structure of a conventional flat yoke type SV head. That is, the head 100C shown in FIG. 15 is a so-called "horizontal" yoke type SV head, and the head 100D shown in FIG. 16 is a so-called "vertical" yoke type SV head.

The plane yoke type head 100 shown in FIG.
C denotes a pair of magnetic yokes 107, 107 formed on the same plane and formed through a magnetic gap, and an SV element unit 102 arranged in a state of being magnetically coupled to them.
A pair of electrodes 103 and 10 arranged at both ends of the SV element portion
3

A vertical yoke type SV shown in FIG.
The head 100D includes a front yoke 107A, a back yoke 107B, a bottom yoke 107C, an SV element 102 magnetically coupled to the front yoke and the back yoke, and a pair of electrodes 103A installed at both ends thereof.
103B.

[0011]

However, in the conventional SV head as illustrated in FIGS. 13 to 16, sufficient output can be obtained by increasing the recording density of the recording medium 200 in any structure. Had the problem of disappearing.

FIG. 17 shows the SV shown in FIGS.
FIG. 2 is a conceptual perspective view illustrating a structure of an SV element provided in a head. As shown in FIG.
It is composed of a magnetization free layer 102A, a magnetization fixed layer 102C, and a nonmagnetic intermediate layer 102B sandwiched therebetween. Each of these layers is formed into a thin film having a flat and uniform thickness.

As the recording density of the recording medium 200 increases, the size of the recording bit to be written becomes smaller, so that the signal magnetic field from the recording bit, that is, the medium detection magnetic field from the magnetic head side becomes very small. On the other hand, in the SV head, the magnetization free layer 102 of the SV element is used.
It is necessary to improve the sensitivity to an external magnetic field by reducing the thickness of A. It is also being studied to reduce the thickness of the nonmagnetic intermediate layer 102B in order to increase the output.

As the magnetization free layer 102A becomes thinner, the SV
The sensitivity of the element 102 itself is improved. However, as the film thickness decreases, the magnetic resistance of the magnetization free layer 102A increases, so that the penetration efficiency of the signal magnetic field penetrating into the SV element 102 in the SV head decreases. Therefore, the shield type SV head 100A illustrated in FIGS.
In the case of 100B, most of the signal magnetic field from the medium is absorbed by the shield portion 105 due to the relative difference in magnetic resistance. That is, a sufficient signal magnetic field does not enter the SV element section 102, and the output of the SV head is reduced.

A similar problem also occurs in the case of a yoke type head. That is, in each of the yoke type magnetoresistive heads 100C and 100D illustrated in FIGS. 15 and 16, the recording signal magnetic field must be indirectly guided from the magnetic yoke to the SV element 102. Therefore, when the thickness of the magnetization free layer 102A of the SV element is reduced, the magnetic resistance of the SV element 102 becomes extremely high, and almost no magnetic flux enters the magnetic sensing portion of the SV element 102 from the magnetic yoke, and the magnetic yoke and the SV The signal magnetic field leaks between the elements, and the output cannot be improved as a head.

As described in detail above, in the conventional SV head, the thickness of the magnetization free layer of the SV element is reduced as the density is increased, the magnetic resistance is increased by the thinning, and a sufficient signal magnetic field is applied to the sense section of the SV element. And it was not possible to expect a high output of the SV head.

The present invention has been made based on the recognition of such a problem. That is, the object is to provide an SV head type magnetoresistive head and a magnetic reproducing device capable of increasing the output by mounting an SV element having a magnetic free layer having low magnetic resistance, high sensitivity and high efficiency. To provide.

[0018]

To achieve the above object, a magnetoresistive head according to the present invention is a magnetoresistive head for detecting a signal magnetic field from a magnetic recording medium, comprising: a magnetization fixed layer; A magnetoresistive element having a magnetization free layer, a nonmagnetic intermediate layer provided between the magnetization fixed layer and the magnetization free layer, and a pair of electrodes connected to both ends of the magnetoresistance effect element. Wherein the signal magnetic field flows from the side of the magnetoresistive element to the center, and the thickness of the magnetization free layer at the sides of the magnetoresistive element is greater than the thickness at the center. It is characterized by having been done.

Alternatively, a magnetoresistive head according to the present invention is a magnetoresistive head for detecting a signal magnetic field from a magnetic recording medium, comprising: a magnetization fixed layer; a magnetization free layer; A non-magnetic intermediate layer provided between the magnetization free layer and a magneto-resistance effect element, and a pair of electrodes connected to both ends of the magneto-resistance effect element,
The signal magnetic field flows from a side portion of the magnetoresistive effect element to a central portion. At the side portion of the magnetoresistive effect element, the magnetization free layer is formed of a material having a first saturation magnetization. In the central portion of the effect element, the magnetization free layer has a second magnetization smaller than the first saturation magnetization.
Characterized by being formed of a material having a saturation magnetization of

Alternatively, the magnetoresistive head according to the present invention is a magnetoresistive head for detecting a signal magnetic field from a magnetic recording medium, wherein the fixed magnetic layer, the free magnetic layer, the fixed magnetic layer, A non-magnetic intermediate layer provided between the magnetization free layer and a magneto-resistance effect element, and a pair of electrodes connected to both ends of the magneto-resistance effect element,
The signal magnetic field flows from the side part of the magnetoresistive element to the center part, and at the side part of the magnetoresistive element, the product of the saturation magnetization of the material forming the magnetization free layer and its thickness is the fourth. 1 and the product of the saturation magnetization of the material constituting the magnetization free layer and the thickness thereof has a second value smaller than the first value in the central portion of the magnetoresistive element. It is characterized by the following.

FIG. 2 is a perspective view showing a schematic structure of a magnetoresistive element of a magnetoresistive head according to the present invention. As shown in the figure, the magnetoresistive element is basically composed of a magnetization free layer made of a soft magnetic material, a magnetization fixed layer, and a non-magnetic intermediate layer sandwiched between them. The magnetization fixed layer is fixed in one direction by an antiferromagnetic film or a hard magnetic film. Recently, there is an anti-parallel magnetization pinned layer in which a non-magnetic intermediate layer is laminated between two soft magnetic layers. The magnetization free layer of the SV head according to the present invention is divided into a center portion and an end portion (or “side portion”) according to the magnitude of the Ms · t product. The Ms · t product at the end is larger than that at the center. In order to increase the Ms · t product at the end, it is effective to increase Ms or increase the thickness of the soft magnetic layer used for the magnetization free layer. Thus, the signal magnetic field can be efficiently guided from the end to the center.

Here, as shown in FIG. 2, it is preferable that the central portion and the end portion are connected through a portion having a certain inclination. Thereby, the signal magnetic field from the medium can be efficiently guided to the magnetic sensing unit.

Further, it is preferable that a pair of electrodes is provided at the center so that only the center serves as a magnetic sensing part. Thereby, a portion where the density of the magnetic flux guided to the magnetization free layer is high and the magnetization rotation of the magnetization free layer is large can be defined as a magnetic sensing portion.
This leads to an improvement in the output of the V head.

Further, it is preferable that the magnetic permeability at the center is larger than or substantially equal to the magnetic permeability at the ends. As a result, the efficiently picked-up signal magnetic field can be efficiently guided to the central portion serving as the magnetically sensitive portion without being released to the shield portion.

Here, as an embodiment of the present invention, the magnetoresistive effect element is arranged so as to be magnetically coupled to a pair of magnetic yokes formed on the same plane so as to face each other via a magnetic gap. Can be

Further, both ends of the magnetization free layer may have magnetic isotropy.

In the case of this type of magnetoresistive head, the signal magnetic field from the medium is indirectly guided to the SV element through the magnetic yoke. Therefore, it is important not only to reduce the magnetic resistance and increase the magnetic permeability of the magnetic yoke, but also to how the magnetic yoke can be drawn into the SV element portion. Therefore, Ms · t at both ends of the magnetization free layer of the SV element portion.
Increasing the product is preferable because magnetic resistance can be reduced. Further, it is preferable that the Ms · t product is large in the overlapping portion with the magnetic yoke.

Further, by making the magnetic anisotropy at the end of the magnetization free layer isotropic, the magnetic resistance in the SV element direction can be further reduced, and the signal magnetic field from the magnetic yoke can be efficiently reduced.
It is possible to guide to the V element portion.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram showing a magnetic head according to a first embodiment of the present invention. That is, FIG. 1A is a partially transparent plan view showing a schematic structure of a plane yoke type magnetoresistive head according to the present invention, and FIG. 1B is a sectional view taken along line AA.

The magnetoresistive head 10A is made of AlOx
-It is formed on the substrate 11A made of Ti.C (Altic) or the like. An insulating layer 11B made of AlOx is formed on the substrate 11A. On the insulating layer 11B, a pair of magnetic yokes 17, 17 made of a magnetic material are formed via a magnetic gap 15. This pair of magnetic yokes,
It is formed on the same plane parallel to the main surface of the substrate 11A. The pair of magnetic yokes 17, 17 may be composed of a single layer of a soft magnetic material such as a NiFe alloy or an amorphous CoZrNb alloy, or may be composed of a laminated film composed of a soft magnetic film and an antiferromagnetic film. Things.
The magnetic anisotropy of the magnetic yoke 17 is controlled to be one-way anisotropic or isotropic.

The SV element 12 includes a pair of magnetic yokes 17,
Part 17 is magnetically coupled to magnetic yoke 17.
Are arranged to overlap.

FIG. 2 is a conceptual perspective view showing the SV element 12 mounted on the magnetic head of this embodiment.

As shown in FIG. 1, the SV element 12 is basically formed by a magnetization free layer (free layer) 12A, a non-magnetic intermediate layer (spacer layer) 12B, and a magnetization fixed layer (pin layer) 12C. You. The magnetization free layer 12A is made of a soft magnetic material, and the magnetization fixed layer 12C is fixed in one direction by an antiferromagnetic film or a hard magnetic film. Further, as the configuration of the magnetization fixed layer 12C, an anti-parallel structure in which a second non-magnetic intermediate layer is stacked between two soft magnetic layers can also be adopted.

The magnetization free layer 12A of the SV head of the present invention
Is divided into a central portion C and an end portion (or “side portion”) E according to the magnitude of the Ms · t product (the product of the saturation magnetization and the film thickness). The Ms · t product at the end E is larger than that at the center C. In the present embodiment, as shown in FIGS. 1 and 2, the case where the film thickness of the magnetization free layer 12 </ b> A at the end portion (side portion) E is increased. In addition to this, as described later in detail, at the end E, the Ms of the magnetization free layer 12A
May be increased. Alternatively, these measures may be combined.

As shown in FIG. 1, Ms · t at both ends E
The portion where the product is large overlaps with the magnetic yoke 17. Thus, the signal magnetic field can be efficiently guided from the end E to the center.

On the other hand, in the central portion C, the magnetization free layer 1
The film thickness of 2A is thin and constant. This allows
The sensitivity to the signal magnetic field can be increased.

As also shown in FIGS. 1 and 2, S
It is preferable that the center portion C and the end portion E of the V element 12 are connected via a sloped portion. As a result, the signal magnetic field can be efficiently guided from the magnetic yoke 17 to the central portion C, that is, the magnetic sensing portion.

On the other hand, the magnetic anisotropy at both ends E is N
It is desirable that a laminated film of a ferromagnetic material film / antiferromagnetic material film such as iFe / IrMn has isotropy. This makes it possible to further reduce the magnetic resistance in the central portion C of the SV element, that is, in the direction of the magnetic sensing portion, as compared with the case where the Ms · t product is merely increased.

At both ends of the SV element 12, a pair of electrodes 13 for supplying a sense current are electrically connected and installed. The electrode 13 is made of Ta (tantalum), Cu
It is made of a material such as (copper), Au (gold), Ti (titanium), and W (tungsten). The “magnetically sensitive portion” is defined by the distance between the pair of electrodes 13. The magnetic sensing part is provided on the electrode 1 so as to be set inside the pair of magnetic yokes 17 and 17.
It is good to arrange 3 and 13. However, this is not always the case when securing a higher output.

Further, in order to control magnetic domains generated in the magnetization free layer 12A of the SV element,
Are magnetically biased at both ends of the SV element 12.

FIG. 3 is a conceptual diagram illustrating the operation of the bias film 18. In the plane yoke type magnetoresistive head according to the present embodiment, the magnetic bias film 18 is magnetically coupled to the magnetization free layer 12A and applies a bias magnetic field in the direction indicated by M in the drawing to make the magnetization free. It has the role of suppressing the generation of magnetic domains in the layer 12A and preventing the generation of Barkhausen noise.

Here, the magnetization fixed direction of the magnetization fixed layer 12C is set such that the magnetization fixed direction of the magnetization fixed layer 12C is substantially parallel to the direction in which the sense current i flows. In this way, the magnetic field Hi due to the sense current i does not affect the bias point, and a large current can flow as the sense current, so that the output can be increased.

Further, as shown in FIG. 3, in the magnetoresistive head according to the present invention, the sense current i is applied so that the sense current magnetic field Hi becomes the same as the magnetization direction M of the magnetic bias film 18. . When power is supplied in the opposite direction,
The sense current magnetic field Hi acts on the magnetization free layer 12A so as to cancel the effect of the magnetic bias film 18, and the bias effect is weakened. As a result, magnetic domains are formed in the magnetization free layer 12A, and Barkhausen noise is easily generated.

On the other hand, when the sense current i is supplied in the direction shown in FIG. 3, Barkhausen noise can be suppressed, and the magnetic bias magnetic field applied to the magnetization fixed layer 12C acts to be canceled out. The effect of stabilizing the direction can also be obtained.

The magnetic bias film 18 is made of a hard magnetic material. For example, it is desirable to use a hard magnetic ferrite film made of Fe.Co.O, a high electric resistance film such as CoPt.SiOx, or an insulating film. It is desirable that the magnetic bias film 18 be electrically insulated from the electrode 13 formed thereon. As a method of securing the insulation between them, an insulating film (not shown) made of AlOx or the like is formed on the magnetic bias film 18 or the contact portion with the electrode 13 is formed by FIB.
There is a method of cutting using a processing method such as (focused ion beam).

Referring back to FIG. 1, the SV element 1
2 is an ABS on the magnetic yoke 17 (anti-bearing surveillance).
face: medium facing surface) is formed on a magnetic gap that is retracted by a predetermined distance from the medium facing surface. This allows SV on the ABS
When the element 12 is not exposed and the magnetic head 10A travels on the recording medium, the magnetic head 10A does not come into contact with the medium and is cut off due to wear. Further, output fluctuation of the head due to heat generated when the head comes into contact with the medium, that is, thermal asperity can be avoided.

FIG. 4 is a perspective view conceptually showing a state where a signal magnetic field flows from the magnetic yoke to the SV element in the magnetic head of the present invention and the conventional magnetic head. FIG.
In the conventional magnetic head shown in FIG.
The thickness of the magnetization free layer 102A is uniform, and if the thickness of the magnetization free layer is reduced for higher sensitivity, the magnetic resistance increases and the inflow of the signal magnetic field H from the magnetic yoke 207 is prevented. Leaked to the outside.

On the other hand, in the magnetic head of the present invention, the magnetic free layer 1
The Ms · t product of 2A is increased. That is, since the magnetic resistance is reduced, the inflow of the signal magnetic field H from the magnetic yoke 17 is not hindered as shown in FIG. The signal magnetic field H that has flowed into the magnetization free layer 12A at the end E having a low magnetic resistance is smoothly introduced into the central part C, that is, the magnetic sensing part via the inclined part of the Ms · t product.
As a result, it is possible to secure a high output by sufficiently taking in the signal magnetic field H while increasing the sensitivity of the magnetization free layer.

As a result of the study by the present inventor, as a result of comparing the output of the plane yoke type magnetoresistive head of the present invention with the output of the conventional plane yoke type magnetoresistive head using the SV element, the output is larger than that of the conventional head. It was confirmed that an output 1.5 times or more was obtained.

Next, a method for fabricating the magnetoresistive head of this embodiment will be described.

FIG. 5 is a schematic process diagram showing a main part manufacturing process of the magnetoresistive head of this embodiment. That is,
5A to 5D show a plan view and a cross-sectional view taken along the line AA in each step, respectively.

In manufacturing a magnetoresistive head, first, as shown in FIG. 5A, a material to be a magnetic yoke is deposited on a substrate. Specifically, AlOx
A on the substrate 11A made of Ti.C (Altic) etc.
An insulating layer 11B made of lOx or the like is formed, and
The magnetic yoke layer 17a is formed by a method such as an evaporation method or a sputtering method. As the magnetic yoke layer 17a, for example, a laminated film made of Ta / NiFe / IrMn / NiFe can be used.

Next, as shown in FIG. 5B, the magnetic yoke layer 17a is patterned. Specifically, a resist mask of the pattern of the magnetic yoke 17 is formed on the magnetic yoke layer 17a by photolithography, and the magnetic yoke layer 17a is etched by dry etching to remove the resist. Here, since the gap of the magnetic gap 15 is minute, it is desirable to process the magnetic gap 15 by FIB or the like. After that, a non-magnetic insulator such as SiOx is buried in the magnetic gap 15 and flattened.

Next, as shown in FIG. 5C, a part 12AE of the magnetization free layer 12A is formed. Specifically, first, a soft magnetic layer Ta / IrMn / NiFe to be a part of the magnetization free layer at the end E of the SV element 12 is formed. Then, a portion corresponding to the central portion C of the magnetization free layer is selectively etched away. For example, both ends of the magnetization free layer 12A are covered with a resist mask by photolithography technology,
In this state, dry etching such as ion milling or reactive ion etching is performed to obtain FIG.
As shown in (c), a part of the magnetization free layer can be left only at both ends E.

Next, as shown in FIG. 5D, an SV film is formed. The laminated structure of the SV film is, for example, NiFe / C
oFe / Cu / CoFe / PtMn / Ta. After the SV film is deposited, patterning is performed by photolithography and dry etching to form the SV element 1
Form 2

Thereafter, a magnetic bias film 18 (not shown) is formed and patterned, and the electrode 13 is formed by a lift-off method.

After the completion of the above wafer process, 270 ° C.-1
0-hour SV element magnetization fixed layer fixed annealing, 200 ° C-
The magnetic yoke and the end of the magnetization free layer are subjected to isotropic annealing for 5 hours, and finally, the magnetic bias film is magnetized in a direction substantially perpendicular to the magnetization direction of the magnetization fixed layer to complete the magnetic head.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described.

FIG. 6 is a conceptual diagram showing a magnetic head according to a second embodiment of the present invention. That is, FIG. 1A is a partially transparent plan view showing a schematic structure of a plane yoke type magnetoresistive head according to the present invention, and FIG. 1B is a sectional view taken along line AA. Referring to FIG.
The same parts as those described above with reference to FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description will be omitted.

The magnetoresistive head 10B of this embodiment
Also, an insulating layer 11B is formed on a substrate 11A, and a pair of magnetic yokes 17
17 is formed, and has an SV element 22, electrodes 13, 13 and bias films 18, 18 formed thereon.

Also in the present embodiment, the SV element 22
Basically, it has a configuration in which a magnetization free layer 22A, a nonmagnetic intermediate layer 22B, and a magnetization fixed layer 22C are stacked. However, in the present embodiment, both ends (both sides) of the magnetization free layer 22A.
E is formed of a material having a high saturation magnetization Ms instead of increasing the film thickness. That is, the magnetization free layer 22A
The end portions E are formed of a material having a relatively high Ms, and the center portion C is formed of a material having a relatively low Ms. Specifically, for example, be formed by the ends E of the magnetization free layer 22A is formed by Co ₉₀ Fe ₁₀ (Ms = 1.8 kilogauss), a central portion _{C Ni 80 Fe 20 (Ms =} 1 kilogauss) Can be.

By using a material having a high Ms, the magnetic resistance can be reduced. As a result, even if the thickness of the magnetization free layer 22A is reduced, the inflow of the signal magnetic field from the magnetic yoke 17 is not hindered.
That is, the signal magnetic field can smoothly flow from the magnetic yoke 17 to the magnetization free layer 22A at the end portion (side portion) E where the magnetic resistance is low, and can be introduced into the central portion C, that is, the magnetic sensing portion. As a result, it is possible to sufficiently capture a signal magnetic field and secure a high output, while reducing the thickness of the magnetization free layer to increase the sensitivity.

Next, a method of manufacturing the magnetoresistive head 10B of this embodiment will be described.

FIG. 7 is a process cross-sectional view showing a main part manufacturing process of the magnetoresistive head 10B of this embodiment.

The state shown in FIG. 5A corresponds to the state shown in FIG. 5C. That is, as described above with reference to the first embodiment, the insulating layer 11B is formed on the substrate 11A, and the magnetic yoke 17 and the magnetic gap 15 are formed. Then, a material having a high Ms such as Co ₉₀ Fe ₁₀ is deposited thereon and patterned as the end 22AE of the magnetization free layer.

Next, as shown in FIG. 7 (b), Ni ₈₀
A low Ms material such as Fe ₂₀ is deposited.

Next, as shown in FIG. 7C, the surface is flattened. Specifically, CMP (chemical mechanical
Etching may be performed by a method such as etching (chemical mechanical polishing), or the central portion C may be masked and the layer 22AE on the end portion E may be removed by etching.

Next, as shown in FIG. 7D, a nonmagnetic intermediate layer 22B and a pinned layer 22C are deposited in this order.
Thereafter, the magnetic head is completed by performing the steps described above with respect to the first embodiment.

As described above, also in the present embodiment, the signal magnetic field smoothly flows from the magnetic yoke layer to the magnetization free layer at the end E having a low magnetic resistance, and is introduced into the central part C, that is, the magnetic sensing part. I can do it. As a result, a high output can be ensured by sufficiently taking in the signal magnetic field while increasing the sensitivity of the magnetization free layer.

Further, according to the present embodiment, it is possible to make the thickness of the magnetization free layer constant. That is, a step is prevented from being formed on the surface of the SV element 22 and the electrode 13
It can also solve problems such as "step break".

(Third Embodiment) Next, a third embodiment of the present invention will be described.
An embodiment will be described.

FIG. 8 is a partially transparent perspective view conceptually showing a main part of a magnetoresistive head according to a third embodiment of the present invention. That is, the magnetic head 10C of FIG.
This is a horizontal type magnetoresistive head using an SV element, and has an SV element 30 provided on a medium 200 in a lateral direction, and a pair of electrodes 13 connected to both ends thereof. S
The V element 30 includes a magnetization free layer 30A and a non-magnetic intermediate layer 30B.
And the magnetization fixed layer 30C. The thickness of the end E of the magnetization free layer 30A on the ABS side is increased, and the Ms · t product is increased. This makes it possible to smoothly introduce the magnetic flux from the medium 200 into the magnetization free layer 30A. That is, it is possible to receive more signal magnetic fields of the magnetization free layer 30A.

In the magnetic head 10C, the electrode 13 is formed at a portion where the thickness of the magnetization free layer 30A is small, that is, at a low M.
It is connected to the part of st product. If you do this,
A portion of the magnetization free layer 30A having a small thickness and a high sensitivity can be set as a "magnetic sensing portion". That is, the thicker end portion of the magnetization free layer 30A plays a role of collecting a signal magnetic field, and the thinner portion serves as a detecting portion for converting the collected signal magnetic field into an electric signal. Fulfill.

This embodiment can be similarly applied to a vertical type magnetoresistive head.

FIG. 9 is a partially transparent perspective view conceptually showing a main part of a magnetoresistive head according to a modification of this embodiment. That is, the magnetic head 10D shown in the figure is a vertical magnetoresistive head using an SV element,
It has an SV element 40 provided in a vertical direction on the zero and a pair of electrodes 13a, 13b connected to both ends thereof.

The SV element 40 has a magnetization free layer 40A, a nonmagnetic intermediate layer 40B, and a magnetization fixed layer 40C, and the thickness of the end E of the magnetization free layer 40A is increased on the ABS side.
The Ms · t product is increased. Also in this modified example,
The magnetic flux from the medium 200 can be smoothly introduced into the magnetization free layer 40A. That is, it is possible to receive more signal magnetic fields of the magnetization free layer 40A.

Also in the magnetic head 10D, the electrodes 13a and 13b are connected so as to conduct electricity to a portion where the thickness of the magnetization free layer 40A is thin, that is, a portion having a low Ms · t product. By doing so, in the magnetization free layer 40A,
The portion where the film thickness is small and the sensitivity is high can be used as the “magnetically sensitive portion”. That is, the thicker end portion of the magnetization free layer 40A plays a role of collecting a signal magnetic field, and the thinner portion serves as a detecting portion for converting the collected signal magnetic field into an electric signal. Fulfill.

Further, in the present modified example, by causing the electrode 13b on the ABS side to be grounded, the occurrence of electrostatic breakdown even when the electrode 13b comes into contact with the recording medium 200 is suppressed. Furthermore, the thermal asperity is enhanced due to the excellent thermal diffusion.

Although FIGS. 8 and 9 show a specific example of increasing the thickness of the magnetization free layer on the ABS side, the present invention is not limited to this. In addition, for example, as described above with respect to the second embodiment, a material may be selected such that Ms of the magnetization free layer becomes higher on the ABS side.

Alternatively, the film thickness and the material of the magnetization free layer may be simultaneously changed so that the Ms · t product of the magnetization free layer on the ABS side becomes higher.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described.
As an embodiment, a magnetic reproducing apparatus according to the present invention will be described. The magnetic head of the present invention described above with reference to FIGS. 1 to 9 is incorporated in, for example, a recording / reproducing integrated magnetic head assembly, and can be mounted on a magnetic reproducing apparatus.

FIG. 10 is a perspective view of an essential part illustrating a schematic configuration of such a magnetic recording apparatus. That is, the magnetic recording / reproducing device 150 of the present invention is a device using a rotary actuator. In the figure, a magnetic disk 200 for longitudinal recording or perpendicular recording has a spindle 1
52, and is rotated in the direction of arrow A by a motor (not shown) responsive to a control signal from a drive device control unit (not shown). The magnetic disk 200 is a recording medium having a recording layer for longitudinal recording or perpendicular recording. In the magnetic disk 200, a head slider 153 for recording and reproducing information stored in the magnetic disk 200 is attached to a tip of a thin-film suspension 154. Here, the head slider 153 has, for example, the magnetic head according to any of the above-described embodiments mounted near the tip thereof.

When the magnetic disk 200 rotates, the medium facing surface (ABS) of the head slider 153 is held with a predetermined flying height from the surface of the magnetic disk 200.

The suspension 154 is connected to one end of an actuator arm 155 having a bobbin for holding a drive coil (not shown). The other end of the actuator arm 155 is provided with a voice coil motor 156, which is a type of linear motor. The voice coil motor 156 includes a drive coil (not shown) wound around a bobbin portion of the actuator arm 155, and a magnetic circuit including a permanent magnet and an opposing yoke, which are opposed to each other so as to sandwich the coil.

The actuator arm 155 has a fixed shaft 1
It is held by ball bearings (not shown) provided at two positions above and below 57, and can be freely rotated and slid by a voice coil motor 156.

FIG. 11 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 as viewed from the disk side. That is, the magnetic head assembly 1
Numeral 60 has an actuator arm 151 having a bobbin for holding a drive coil, for example. A suspension 154 is connected to one end of the actuator arm 155.

A head slider 153 having one of the reproducing magnetoresistive heads described above with reference to FIGS. 1 to 9 is attached to the tip of the suspension 154. A recording head may be combined. The suspension 154 has lead wires 164 for writing and reading signals, and the lead wires 164 are electrically connected to the respective electrodes of the magnetic head incorporated in the head slider 153. In the figure, reference numeral 165 denotes an electrode pad of the magnetic head assembly 160.

Here, between the medium facing surface (ABS) of the head slider 153 and the surface of the magnetic disk 200,
A predetermined flying height is set.

FIG. 12A is a conceptual diagram showing the relationship between the head slider 153 and the magnetic disk 200 when the flying height is a predetermined positive value. As illustrated in the figure, usually, in many magnetic recording devices, the slider 153 on which the magnetic head 10 is mounted operates while flying above the surface of the magnetic disk 200 by a predetermined distance. In the present invention, even in such a "flying traveling" type magnetic recording device, reproduction with higher resolution and higher output and lower noise can be performed as compared with the related art. That is, by employing any of the magnetoresistive heads described above with reference to FIGS. 1 to 9, the signal magnetic field can be smoothly introduced while increasing the sensitivity of the SV element. That is, even when the recording density of the magnetic disk 200 is increased and the medium magnetization is reduced, reproduction with high sensitivity and high output and low noise can be performed.

On the other hand, when the recording density is further increased, it is necessary to read the information by lowering the flying height and gliding closer to the magnetic disk 200. For example, in order to obtain a recording density of about 30 G (giga) bits per square inch, the spacing loss due to flying is too large, and the head 10 and the magnetic disk 200 crash due to extremely low flying. Problem cannot be ignored.

For this reason, a method is also conceivable in which the magnetic head 10 and the magnetic disk 200 are made to come into contact with each other in a positive manner and run.

FIG. 12B is a conceptual diagram showing the relationship between such a “contact running type” head slider 153 and the magnetic disk 200. Also in the magnetic head of the present invention, DLC (Diamond-Like-Carbon) is provided on the contact surface with the medium.
By providing a lubricating film or the like, it can be mounted on a “contact traveling type” slider. Therefore, FIG.
In the "contact running type" magnetic reproducing device as exemplified in the above, the small signal magnetic field from the recording bit reduced by the high density is reliably input and detected with high sensitivity, thereby achieving low noise and stable. Playback can be performed.

The embodiments of the present invention have been described with reference to the examples. However, the present invention is not limited to these specific examples. For example, as long as the magnetoresistive element has a magnetization free layer, a non-magnetic intermediate layer, and a magnetization fixed layer, it can be selected from any structures and materials that can be selected by those skilled in the art, in addition to those listed as specific examples. It is possible to use it.

Similarly, the material and shape of each element constituting the magnetic head are not limited to those described above as specific examples, and the same effects can be obtained by using all the ranges that can be selected by those skilled in the art. Can be played.

The magnetic reproducing device may be one that performs only reproduction or one that performs recording and reproduction. The medium is not limited to a hard disk, but may be a flexible disk or a magnetic card. It is possible to use any magnetic recording medium such as. Further, the apparatus may be a so-called "removable" type apparatus in which the magnetic recording medium is removable from the apparatus.

[0097]

As described in detail above, according to the present invention,
A signal magnetic field from the recording medium can be efficiently guided to the magnetization free layer of the SV element, and a weak signal magnetic field from a minute recording bit can be reliably reproduced. As a result, it is possible to provide a magnetoresistive head capable of greatly improving the recording density of a magnetic recording medium and a magnetic reproducing apparatus using the same,
The merit in the magnetic recording related industry is very large.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a magnetic head according to a first embodiment of the present invention. That is, FIG. 1A is a partially transparent plan view showing a schematic structure of a plane yoke type magnetoresistive head according to the present invention, and FIG. 1B is a sectional view taken along line AA.

FIG. 2 is a conceptual perspective view showing an SV element 12 mounted on the magnetic head according to the first embodiment of the present invention.

FIG. 3 is a conceptual diagram illustrating the operation of a bias film.

FIG. 4 is a perspective view conceptually showing how a signal magnetic field flows from a magnetic yoke to an SV element in the magnetic head of the present invention and a conventional magnetic head.

FIG. 5 is a schematic process diagram illustrating a main part manufacturing process of the magnetoresistive head according to the first embodiment of the present invention. That is, FIGS. 5A to 5D respectively show a plan view and a cross-sectional view taken along line AA in each step.

FIG. 6 is a conceptual diagram illustrating a magnetic head according to a second embodiment of the present invention. That is, FIG. 1A is a partially transparent plan view showing a schematic structure of a plane yoke type magnetoresistive head according to the present invention, and FIG. 1B is a sectional view taken along line AA.

FIG. 7 is a process cross-sectional view illustrating a main part manufacturing process of the magnetoresistive head 10B according to the second embodiment of the present invention.

FIG. 8 is a partially transparent perspective view conceptually showing a main part of a magnetoresistive head according to a third embodiment of the present invention.

FIG. 9 is a partially transparent perspective view conceptually showing a main part of a magnetoresistive head according to a modification of the third embodiment of the present invention.

FIG. 10 is a perspective view of an essential part illustrating a schematic configuration of a magnetic recording apparatus of the present invention.

FIG. 11 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 as viewed from the disk side.

FIG. 12A is a conceptual diagram showing the relationship between the head slider 153 and the magnetic disk 200 when the flying height is a predetermined positive value, and FIG. 12B is such a “contact traveling type”.
FIG. 3 is a conceptual diagram showing a relationship between the head slider 153 and the magnetic disk 200.

FIG. 13 is a perspective view conceptually showing the structure of a conventional “horizontal” shield type SV head.

FIG. 14 is a perspective view conceptually showing the structure of a conventional “vertical” shield type SV head.

FIG. 15 is a perspective view illustrating a conventional “horizontal” yoke type SV head.

FIG. 16 is a perspective view showing a conventional “vertical” yoke type SV head.

FIG. 17 is a conceptual perspective view showing the structure of an SV element provided in the SV head shown in FIGS.

[Explanation of symbols]

10A to 10D, 100A to D Magnetoresistive head 11A Substrate 11B Insulating film 12, 22, 30, 40102 Spin valve element (S
V element) 12A, 22A, 30A, 40A, 102A Free magnetic layer (free layer) 12B, 22B, 30B, 40B, 102B Nonmagnetic intermediate layer (spacer layer) 12C, 22C, 30C, 40C, 102C Fixed magnetic layer (pin) 13, 103 Electrode 15 Magnetic gap 17, 107 Magnetic yoke 18 Magnetic bias unit 150 Magnetic recording / reproducing device 152 Spindle 153 Head slider 154 Suspension 155 Actuator arm 156 Voice coil motor 160 Magnetic head assembly 200 Medium (magnetic recording disk)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuichi Osawa 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Pref. Address Toshiba Kawasaki Office (72) Inventor Takashi Koizumi 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture F-term (reference) 5D034 BA05 BA09 BA16 BA18 BA30

Claims (4)

[Claims] 1. A magnetoresistive head for detecting a signal magnetic field from a magnetic recording medium, comprising: a magnetization fixed layer, a magnetization free layer, and a space between the magnetization fixed layer and the magnetization free layer. A magnetoresistive element having a non-magnetic intermediate layer; and a pair of electrodes connected to both ends of the magnetoresistive element, wherein the signal magnetic field flows from a side part of the magnetoresistive element to a central part. And a film thickness of the magnetization free layer in the side portion of the magnetoresistive element is larger than a film thickness in the central portion. 2. A magnetoresistive head for detecting a signal magnetic field from a magnetic recording medium, comprising: a magnetization fixed layer; a magnetization free layer; and a space between the magnetization fixed layer and the magnetization free layer. A magnetoresistive element having a non-magnetic intermediate layer; and a pair of electrodes connected to both ends of the magnetoresistive element, wherein the signal magnetic field flows from a side part of the magnetoresistive element to a central part. The magnetization free layer is formed of a material having a first saturation magnetization in the side portions of the magnetoresistive element, and the magnetization free layer is formed of the first material in the central portion of the magnetoresistive element. A magnetoresistive head comprising a material having a second saturation magnetization smaller than the saturation magnetization. 3. A magnetoresistive head for detecting a signal magnetic field from a magnetic recording medium, comprising: a magnetization fixed layer, a magnetization free layer, and a space between the magnetization fixed layer and the magnetization free layer. A magnetoresistive element having a non-magnetic intermediate layer; and a pair of electrodes connected to both ends of the magnetoresistive element, wherein the signal magnetic field flows from a side part of the magnetoresistive element to a central part. In the side portion of the magnetoresistive element, the product of the saturation magnetization of the material forming the magnetization free layer and the thickness thereof is 1st.
In the central portion of the magnetoresistive effect element, the product of the saturation magnetization of the material forming the magnetization free layer and the thickness thereof has a second value smaller than the first value. A magnetoresistive head comprising: 4. A magnetic reproducing apparatus comprising the magnetoresistive head according to claim 1, wherein the magnetic information can be reproduced from magnetic information stored in a magnetic recording medium.