JP2006085880A - Magnetic head using CPP spin valve element and magnetic recording / reproducing apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a magnetoresistive change rate without substantially deteriorating soft magnetic characteristics of a free layer, and to provide a magnetic head using a CPP spin valve element with improved durability against element breakdown, and a magnetic head using the same A recording / reproducing apparatus is provided.
A magnetic head using a CPP spin valve element according to the present invention includes a nonmagnetic intermediate layer between two or more ferromagnetic layers, and a current is perpendicular to the ferromagnetic layer and the nonmagnetic intermediate layer. In the magnetic head using the CPP spin valve element that is energized, at least one of the two or more ferromagnetic layers is made of a Co _X Fe _100-X alloy (where X = 60 to 80 [atomic%]). ).
[Selection] Figure 1

Description

  The present invention relates to a magnetic head and a magnetic recording / reproducing apparatus using the same. More specifically, the present invention relates to a magnetic head using a CPP spin valve element and a magnetic recording / reproducing apparatus using the magnetic head.

  In recent years, magnetic disk media such as hard disk drives (HDD) are required to be reduced in size and capacity. In order to satisfy these demands simultaneously, it is necessary to increase the recording density of magnetic disk media.

Conventionally, information recorded on a magnetic disk medium is read out by moving a reproducing magnetic head having a coil relative to the magnetic disk medium, and generating an electric current induced in the coil by electromagnetic induction generated at that time. It has been done by a method of detecting.
However, due to the smaller recording bit size associated with higher recording density and the accompanying weakening of magnetic force, the conventional MIG (Metal In Gap) head and thin film (Thin Film) heads have insufficient reproduction sensitivity. At present, in a magnetic recording / reproducing apparatus such as an HDD, a magnetoresistive head (MR head) using a magnetoresistive effect element (MR element) is used as a read-only magnetic head.

  Recently, a giant magnetoresistive head (GMR head) using a giant magnetoresistive effect element (GMR element) that exhibits a greater magnetoresistive effect has been developed to achieve higher recording density. Expectations are growing.

  In the GMR element, an underlayer / an antiferromagnetic layer / a first ferromagnetic layer / a nonmagnetic intermediate layer / a second ferromagnetic layer / a protective layer are formed on a lower electrode (substrate) by several nanometers to several dozens, respectively. It has a structure in which the layers are sequentially stacked with a thickness of nm. Here, the first ferromagnetic layer is called a pinned layer or a magnetization fixed layer, and is a magnetic layer whose magnetization direction is substantially fixed in one direction. The second ferromagnetic layer is called a free layer or a magnetization free layer, and is a magnetic layer whose magnetization direction can be freely changed according to an external magnetic field.

  Usually, the GMR element has a first ferromagnetic layer / nonmagnetic intermediate layer / second ferromagnetic layer sandwich structure in which the magnetization direction of the first ferromagnetic layer and the magnetization direction of the second ferromagnetic layer are the same. When the current flows from the upper electrode to the lower electrode in a different direction, electrons flow through the nonmagnetic intermediate layer, but a part of the electrons strike the first ferromagnetic layer and scatter, increasing the resistance. Also, the GMR element has a first strong magnetic field when the magnetization direction of the second ferromagnetic layer is reversed depending on the direction of the magnetic field received from the rotating magnetic disk medium, and when the magnetization direction is the same as the magnetization direction of the first ferromagnetic layer. The number of electrons that collide with the wall of the magnetic layer and scatter is reduced and the resistance is reduced. A film having such an action is called a spin valve film (see Non-Patent Document 1 and Non-Patent Document 2), and the change rate of resistance generated in this way is called a magnetoresistance change rate (MR change rate).

  The GMR head has a current-in-plane (CIP-GMR head) structure (hereinafter referred to as a CIP-GMR head) in which a current flows in a direction parallel to the (giant) magnetoresistive element film surface, and a (giant) magnetic current. There is a CPP (Current-Perpendicular-to-Plane) type structure (hereinafter referred to as a CPP-GMR head) that flows in a direction perpendicular to the resistive effect element film surface. Since there is a report that the CPP-GMR head exhibits an MR change rate about 10 times that of the CIP-GMR head (see Non-Patent Document 3), a reproducing head that can meet the demand for higher density recording is available. It is expected to be one of the promising candidates, and research and development are currently under way.

Non-Patent Document 4 and Patent Document 1 describe CPP-GMR elements using Co ₉₀ Fe ₁₀ and Co ₅₀ Fe ₅₀ as typical examples of CPP-GMR elements used in the CPP-GMR head. ing. Further, Non-Patent Document 5 and Patent Document 2 propose a CPP-GMR element using a current confinement structure in order to improve the MR ratio. Here, the current confinement structure refers to a structure that effectively reduces the element size and increases the resistance change amount by narrowing the current flow path.
JP 2003-60263 (paragraphs 0082, 0104, 0106, 0108, 0111, 0113, 0115, 0119, 0124, 0128, 0129, 0131) JP 2003-153248 A (paragraphs 0033, 0076, 0080 to 93, FIGS. 2, 3, 7) Phys. Rev. B, vol. 45, p806 (1992) J. Appl. Phys., Vol. 69, p4774 (1981) J. Phys. Condens. Matter., Vol.11, p5717 (1999) J. Appl. Phys., Vol. 92, p2646 (2002) IEICE technical report MR2004-2, p7, The Institute of Electronics, Information and Communication Engineers

However, in the conventional CPP-GMR element, since the resistance of the portion contributing to the magnetoresistance change is small, the MR change rate cannot be sufficiently increased. That is, since the MR change rate is not sufficient, there is a problem that the head sensitivity cannot be sufficiently increased even when such a CPP-GMR element is used for a reproducing head. It has also been suggested that the MR change rate can be improved by using a CPP-GMR element using Co ₅₀ Fe ₅₀ for the second ferromagnetic layer. It was found that the property of being easily magnetized when a magnetic field is applied from the outside is poor.

  In addition, in the CPP-GMR element using the current confinement structure, although the MR change rate is large, the current density in the constricted portion is large, so that there is a problem in durability against element migration.

  Accordingly, an object of the present invention is to improve the magnetoresistance change rate (MR change rate) without substantially deteriorating the soft magnetic characteristics of the second ferromagnetic layer (so-called free layer), and to withstand the element breakdown. It is an object of the present invention to provide a magnetic head using a CPP spin-valve element with improved C and a magnetic recording / reproducing apparatus using the same.

An object of the present invention is to provide a magnetic head using a CPP spin-valve element that includes a nonmagnetic intermediate layer between two or more ferromagnetic layers, and supplies a current to the ferromagnetic layer or the nonmagnetic intermediate layer in a plane. in, among the two or more ferromagnetic layers, at least the one layer, characterized in that a layer containing a Co _X Fe _100-X alloy (where, X = 60-80 [atomic%]) CPP This is achieved by a magnetic head using a spin valve element.

  According to the magnetic head using the CPP spin valve element of the present invention having such a configuration, since the composition of the CoFe alloy is optimized, the magnetization direction of the first ferromagnetic layer of the CPP spin valve element and the second Between the magnetoresistance when the magnetization direction of the ferromagnetic layer is different and the magnetoresistance when the magnetization direction of the first ferromagnetic layer and the magnetization direction of the second ferromagnetic layer are the same direction Although the magnetoresistive change rate (MR change rate) is improved, the soft magnetic characteristics of the second ferromagnetic layer are hardly deteriorated. In addition, since the magnetic head using the CPP spin valve element of the present invention does not use the current confinement structure, the durability against element destruction is not impaired.

Another object of the present invention is to provide the CPP spin valve element further having an antiferromagnetic layer, and using this antiferromagnetic layer, the magnetization direction of any one of the two or more ferromagnetic layers is fixed. This is achieved by a magnetic head using the CPP spin valve element according to claim 1 (claim 2).
As described above, in the magnetic head using the CPP spin valve element of the present invention, the magnetization direction of the ferromagnetic layer is fixed in a substantially constant direction by fixing the ferromagnetic layer using the antiferromagnetic layer. can do. Further, by fixing the magnetization direction in this way, it is possible to improve the resistance to external magnetic fields.

The object of the present invention is to provide a CPP spin valve according to claim 1 or 2, wherein a NiFe alloy is laminated on the ferromagnetic layer of which the magnetization direction is not fixed in the antiferromagnetic layer. This is achieved by a magnetic head using the element.
Thus, in the magnetic head using the CPP spin valve element of the present invention, the NiFe alloy is laminated on the ferromagnetic layer not fixed by the antiferromagnetic layer, so that the soft magnetic characteristics are improved and the magnetic head Sensitivity is improved.

According to another aspect of the present invention, Cu is laminated on a ferromagnetic layer that is not fixed by the antiferromagnetic layer, or a magnetic head using a CPP spin valve element according to claim 2, (Claim 4).
As described above, since the magnetic head using the CPP spin valve element of the present invention has a CoFe / Cu stacked structure, among the electrons spin-polarized into majority spins and minority spins, electrons having minority spins are stacked in this stack. Since it can be scattered at the interface of the structure, the MR change rate can be improved and the sensitivity as a magnetic head can be improved. In addition, MR change rate can be improved, so that there are many this interfaces.

Furthermore, the object of the present invention is achieved by providing a magnetic recording / reproducing apparatus using the magnetic head using the CPP spin valve element according to any one of claims 1 to 4. (Claim 5).
With this configuration, since the magnetic head using the CPP spin valve element according to the present invention is provided, the soft magnetic characteristics of the second ferromagnetic layer (so-called free layer) and the magnetoresistance change rate (MR) It is possible to realize a magnetic recording / reproducing apparatus having excellent change rate and durability against element destruction.

According to the magnetic head using the CPP spin valve element of the present invention, the magnetoresistance change rate (MR change rate) is improved without substantially deteriorating the soft magnetic characteristics of the second ferromagnetic layer (so-called free layer). And the durability against device destruction can be improved.
Further, according to the magnetic recording / reproducing apparatus of the present invention, the second ferromagnetic layer (so-called free layer) has excellent soft magnetic characteristics, magnetoresistance change rate (MR change rate), and durability against element breakdown. It can be.

  Next, a magnetic head using the CPP spin valve element of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1A is a conceptual diagram showing a configuration of an example of a CPP spin valve laminated film used in the CPP spin valve element of the present invention, and FIG. 1B is a CPP spin valve element of the present invention. It is a conceptual diagram which shows the structure of another example of the CPP spin-valve laminated film used for FIG. FIG. 2 is a cross-sectional view of an essential part showing an example of the configuration of a magnetic head using the CPP spin valve element of the present invention, and FIG. 3 is a magnetic recording using the magnetic head using the CPP-GMR element of the present invention. It is a block diagram which shows the structure of a reproducing | regenerating apparatus.

As shown in the conceptual diagram of FIG. 1A, as an example of the CPP spin valve laminated film 2 used in the CPP spin valve element 1 (see FIG. 2) of the present invention, [substrate 3 / underlayer 4 / Antiferromagnetic layer 5 / first ferromagnetic layer 6 / nonmagnetic intermediate layer 7 / second ferromagnetic layer 8 / protective layer 9].
In the magnetic head 13 using the CPP spin valve element 1 of the present invention, as shown in the sectional view of the main part of FIG. The upper electrode 11 is disposed on the protective layer 9, and the periphery of the CPP spin valve laminated film 2 is covered with the hard film 12. Therefore, when a constant current (sense current) is passed between the lower electrode 10 disposed under the substrate 3 and the upper electrode 11 disposed on the protective layer 9, the sense current is Current is passed in a direction perpendicular to the film surface of the CPP spin valve laminated film 2 sandwiched between the upper electrode 11 and the upper electrode 11. The lower electrode 10 and the upper electrode 11 can be suitably configured by using NiFe or the like.

In the CPP spin valve laminated film 2, the magnetoresistive effect is a laminated portion of [first ferromagnetic layer 6 / nonmagnetic intermediate layer 7 / second ferromagnetic layer 8]. In this laminated portion, a spin-dependent resistance is generated for spin-polarized electrons, and a spin-dependent resistance is generated. Note that the MR change rate of the CPP spin valve element 1 (CPP-GMR element) is the spin-dependent scattering between the second ferromagnetic layer 8 and the nonmagnetic intermediate layer 7, the first ferromagnetic layer 6 and the second ferromagnetic layer 6. Determined by spin-dependent bulk scattering in the ferromagnetic layer 8. Therefore, it is preferable to use a material that increases spin-dependent scattering in relation to the nonmagnetic intermediate layer 7 for the first ferromagnetic layer 6 and the second ferromagnetic layer 8. It is preferable to use a material having a large spin-dependent bulk scattering for a portion that occupies most of the area. With such a configuration, the MR change rate can be increased.
Hereinafter, the configuration of the CPP spin valve laminated film 2 will be described.

Substrate 3 can be suitably indicate that constructed using Al ₂ O ₃ -TiC (AlTiC), it is not limited thereto, may be constituted by Si (silicon).

  The underlayer 4 has a function of improving the crystallinity of a first ferromagnetic layer 6 (pinned layer), which will be described later, and a function of improving the smoothness of the interface between the underlayer 4 and the first ferromagnetic layer 6. It is desirable to form with material. Examples of such a material include Cu (copper) and Ta (tantalum), and it is possible to use only one layer of Cu or Ta, but it is preferable to use it as a Ta / Cu laminate. Further, the thickness of the underlayer 4 is preferably about 300 to 800 nm. With such a thickness, the current distribution in the CPP spin valve element 1 can be made uniform.

  The thickness of the underlying layer 4 is not limited to this, and the thickness can be adjusted as appropriate as long as the current distribution in the CPP spin valve element 1 can be made uniform. For example, in the case of a magnetic head 13 using a CPP spin valve element 1 having a NiFe electrode (magnetic shield) plated with NiFe with a thickness of 1 μm on a substrate 3 such as an Altic substrate, the thickness of the underlayer 4 is approximately It can be provided with a thickness of about 5 μm. In such a configuration, even if the underlayer 4 has a relatively thin thickness, the function of improving the crystallinity of the first ferromagnetic layer 6 and the interface between the underlayer 4 and the first ferromagnetic layer 6 are improved. The function of improving the smoothness and the function of making the current distribution in the CPP spin valve element 1 uniform can be satisfactorily provided.

  The antiferromagnetic layer 5 has a role of fixing the magnetization of the first ferromagnetic layer 6 in one direction using an exchange coupling bias magnetic field generated at the interface. As such a material, IrMn (iridium manganese) is preferably used, but PtMn (platinum manganese), PdPtMn (palladium platinum manganese), NiMn (nickel manganese), and the like can also be used. The thickness of the antiferromagnetic layer 5 is preferably about 5 to 15 nm for IrMn, and about 5 to 30 nm for PtMn or NiMn.

The first ferromagnetic layer 6 is a magnetic layer (pinned layer) having a magnetization substantially fixed in one direction under the action of the antiferromagnetic layer 5. The first ferromagnetic layer 6 is preferably composed of a CoFe alloy with a thickness of 0.5 to 5 nm, and the composition ratio thereof is Co _X Fe _100-X alloy (where X = 60 to 80 [Atom%]) is preferable. When the composition ratio X of Co (cobalt) and Fe (iron) is less than 60 atomic% or exceeds 80 atomic%, the magnetic stability is significantly reduced (see FIG. 4), and a magnetic head with stable performance is realized. I can't. The thickness of the first ferromagnetic layer 6 is preferably about 2 to 7 nm.
The first ferromagnetic layer 6 may be a synthetic ferri pinned layer made of CoFe / Ru / CoFe.

  The nonmagnetic intermediate layer 7 has a role of blocking the magnetic coupling between the first ferromagnetic layer 6 and the second ferromagnetic layer 8, and further from the first ferromagnetic layer 6 to the second ferromagnetic layer 8. It is necessary to have a role of forming an interface between the nonmagnetic intermediate layer 7 and the first ferromagnetic layer 6 so that spin-polarized electrons flowing into the surface are not scattered. The nonmagnetic intermediate layer 7 is made of, for example, Cu (copper), Au (gold), Ag (silver), Re (rhenium), Os (osmium), Ru (ruthenium), Ir (iridium), Pd (palladium), Cr (Chromium), Mg (magnesium), Al (aluminum), Rh (rhodium), Pt (platinum), or the like can be used. The thickness of the nonmagnetic intermediate layer 7 is so thick that the magnetic coupling between the first ferromagnetic layer 6 and the second ferromagnetic layer 8 can be sufficiently blocked, and the electrons from the second ferromagnetic layer 8 However, it is preferable that the thickness of the nonmagnetic intermediate layer 7 is approximately 0.5 to 5 nm, although it is necessary to be as thin as possible.

The second ferromagnetic layer 8 is a magnetic layer (free layer) whose magnetization direction can be freely changed according to an external magnetic field. Similar to the first ferromagnetic layer 6, the second ferromagnetic layer 8 is made of Co _x Fe _100-X alloy (where X = 60 to 80 [atomic%]) and has a thickness of 0. It is preferable that the thickness is about 5 to 7 nm. When the Co composition ratio X is less than 60 atomic%, the Fe composition ratio increases and the soft magnetic characteristics deteriorate, so that the element sensitivity decreases and the sensitivity as a magnetic head decreases. In order to prevent such a decrease in the sensitivity of the magnetic head, it is necessary that the soft magnetic characteristics be 30 Oe or less, that is, the Fe composition ratio is 40 atomic% or less (see FIG. 4). On the other hand, when the Co composition ratio X exceeds 80 atomic%, the MR change rate decreases and the reproduction sensitivity decreases.

Note that the first ferromagnetic layer 6 either (wherein, X = 60-80 [atomic%]) also is Co _X Fe _100-X alloy of the second ferromagnetic layer 8 is preferably a, these If any one of these layers is a CoFe alloy having such a composition, it is possible to obtain the desired soft magnetic characteristics, MR change rate, and durability against element breakdown. Only one layer of the ferromagnetic layer 6 or the second ferromagnetic layer 8 may be made of a Co _x Fe _100-X alloy (where X = 60 to 80 [atomic%]).

Similarly to the first ferromagnetic layer 6, the second ferromagnetic layer 8 can be composed of only one layer of a CoFe alloy, but a layer (insertion layer 81) that improves soft magnetic properties such as a NiFe alloy. ) To form a CoFe / NiFe laminate. Moreover, it can also be set as the laminated body of NiFe / CoFe, NiFe / CoFe / NiFe, and CoFe / NiFe / CoFe.
Furthermore, it is possible to improve the MR ratio by stacking Cu.

  The protective layer 9 plays a role of preventing the deterioration of characteristics of the antiferromagnetic layer 5, the first ferromagnetic layer 6, and the second ferromagnetic layer 8 when the upper electrode 11 is formed. The thickness of the protective layer 9 is preferably about 0.5 to 5 nm.

  When the magnetic head 13 using the CPP spin valve element 1 including the multilayer film having the above-described configuration flows a sense current from the upper electrode 11 toward the lower electrode 10, the film of the CPP spin valve multilayer film 2 is obtained. Electricity is applied in a direction perpendicular to the surface. At this time, under the influence of the weak magnetization of the rotating magnetic disk medium 32 (see FIG. 3), the direction of the magnetization is detected with high sensitivity. That is, the magnetization direction of the second ferromagnetic layer 8 also changes depending on the magnetization direction of the magnetic disk medium 32, and the electric resistance value of the current flowing therethrough changes (magnetoresistance change rate (MR change rate)). . Since the magnetic head 13 using the CPP spin valve element 1 according to the present invention has a large MR change rate, information recorded on the magnetic disk medium 32 can be reproduced satisfactorily.

Here, as the magnetic recording / reproducing apparatus 30 that can be used in the present invention, a conventionally known magnetic recording / reproducing apparatus other than the magnetic head 13 using the CPP spin valve element 1 can be suitably used, and a head stack assembly can be used. It can use suitably also.
As such a magnetic recording / reproducing apparatus 30, for example, in a case 31, a magnetic disk medium 32, a magnetic head 13, a signal processing apparatus (not shown), a voice coil motor 33 and its control unit (not shown). And a spindle motor (not shown) and its controller (not shown).

  As shown in FIG. 2, the magnetic head 13 reproduces the data written on the magnetic disk medium 32 and the write magnetic head section 13b for writing the signalized data on the magnetic disk medium 32. The magnetic head 13 using the CPP spin valve element 1 according to the present invention constitutes the magnetic head part 13a for reading. To do. Since the CPP spin valve element 1 according to the present invention used for the read magnetic head portion 13a has a larger MR change rate than the conventional CPP spin valve element 1, the magnetic bit recorded on the magnetic disk medium 32 is weak. It is possible to detect the magnetization direction of a strong magnetic force with high sensitivity.

  Next, an embodiment relating to the magnetic head 13 using the CPP spin valve element 1 of the present invention will be described.

In the CPP spin valve element 1 of the present invention, a magnetic shield serving also as the lower electrode 10 made of NiFe (1 μm) is formed on an AlTiC substrate by a plating method. Then, a CPP spin valve laminated film 2 for forming the CPP spin valve element 1 of the present invention is laminated on the NiFe. The laminated structure is Ta (5 nm) / Cu (5 nm) / IrMn (10 nm) / Co _x Fe _100-x (4 nm) / Cu (3 nm) / Co _x Fe _100-x (7 nm) / Cu (5 nm) / Ta (5 nm).
These layers were sequentially laminated from the substrate 3 side using an ion beam sputtering apparatus. The values in parentheses represent the thickness of each layer.

Further, the composition of Co _x Fe _100-X in this example has three types of X = 90 [atomic%], 75 [atomic%], and 40 [atomic%], that is, Co ₉₀ Fe ₁₀ and Co ₇₅ Fe _25. Three samples of CPP spin valve laminated films of Co ₄₀ Fe ₆₀ were prepared.

The sputtering conditions by the ion beam sputtering apparatus were as follows: temperature: room temperature, gas pressure: 4 × 10 ⁻⁴ torr, beam voltage: 850 V, beam current: 100 mA. The sputtering rates for sputtering each layer were Cu: 0.25 nm / s, CoFe: 0.08 nm / s, IrMn: 0.1 nm / s, Ta: 0.07 nm / s.

In this CPP spin valve laminated film 2, Ta / Cu laminated on the substrate 3 is the underlayer 4, IrMn is the antiferromagnetic layer 5, and 4 nm of Co _x Fe _100-x is the first 1 is a pinned layer in which the magnetization direction is fixed, and Cu laminated thereon is a nonmagnetic intermediate layer 7, and 7 nm of Co _X Fe _100-X is a second strong layer. The magnetic layer 8 is a free layer whose magnetization direction can be changed by an external magnetic field, and Ta stacked thereon is a protective layer 9. An upper electrode 11 is disposed on the protective layer 9, and a lower electrode 10 is disposed under the substrate 3.

Then, after the CPP spin valve laminated film 2 is formed, in order to give a certain magnetization direction to the antiferromagnetic layer 5, 1000 Oe (Oersted; 1 Oe = (1 / 4π) × 10 ³ A / m) A heat treatment was performed at a temperature of 260 ° C. for 2 hours while applying a magnetic field (in a relationship of ampere per meter).

The magnetic properties of the three samples of Co ₉₀ Fe ₁₀ , Co ₇₅ Fe ₂₅ , and Co ₄₀ Fe ₆₀ produced in this manner in the CPP spin valve laminated film 2 were measured using a vibrating sample magnetometer (VSM). The result is shown in FIG. FIG. 4 shows the soft magnetic characteristics (Hc) of the free layer (second ferromagnetic layer 8) with respect to the Co composition ratio, and the shift amount (Hua) from the zero point of the pinned layer (first ferromagnetic layer 6). It is a graph which shows the relationship. The zero point means a state without magnetism, and the shift amount means the unidirectional anisotropy of the BH curve from the zero point. The shift amount from the zero point is an index indicating the stability of magnetic force, and the larger the value, the less affected by the external magnetic field.

  As shown in FIG. 4, it has been found that the Hc of the free layer exhibiting soft magnetic characteristics decreases as the Co composition ratio increases. Specifically, by setting the Co composition ratio to 40 to 75 atomic%, it was possible to obtain 18.9 Oe, which is half or less when the Co composition ratio is less than 40 atomic%. It is known that this soft magnetic property can be further improved by laminating a soft magnetic layer. In the present invention, this can be improved by laminating a soft magnetic layer such as NiFe. Is possible.

  Further, it has been found that Hua indicating the shift amount from the zero point of the pinned layer increases when the Co composition ratio is 40 to 75 atomic%, compared to when the Co composition ratio is 90 atomic%. That is, the magnetic stability of the pinned layer can be improved by setting the Co composition ratio to 40 to 75 atomic%.

  Table 1 shows the CPP-GMR characteristics when the Co composition ratio is 75 atomic% and 90 atomic%. From this table, by setting the Co composition ratio to 75 atomic%, the MR ratio is improved by 1.5 times compared to the CPP spin-valve laminated film 2 having a Co composition ratio of 90 atomic%. I understood.

As described above, the magnetic head using the CPP spin valve element of the present invention has the soft magnetic characteristics almost deteriorated because the composition ratio of the Co _X Fe _100-X alloy and the laminated structure of the element are appropriate. It was possible to improve the magnetoresistance change rate (MR change rate).

(A) is a conceptual diagram which shows the structure of an example of the CPP spin-valve laminated film used for the CPP spin-valve element of this invention, (b) is a CPP spin-valve laminated film used for the CPP spin-valve element of this invention. It is a conceptual diagram which shows the structure of another example. It is principal part sectional drawing which shows an example of a structure of the magnetic head using the CPP spin valve element of this invention. It is a block diagram which shows the structure of the magnetic recording / reproducing apparatus using the magnetic head using the CPP-GMR element of this invention. It is a graph which shows the relationship between the soft magnetic characteristic (Hc) of a free layer with respect to the composition ratio of Co, and the shift amount (Hua) from the zero point of a pinned layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 CPP spin valve element 2 CPP spin valve laminated film 3 Substrate 4 Underlayer 5 Antiferromagnetic layer 6 First ferromagnetic layer 7 Nonmagnetic intermediate layer 8 Second ferromagnetic layer 9 Protective layer 10 Lower electrode 11 Upper electrode 12 Hard film 13 Magnetic head 13a Magnetic head part for reading 13b Magnetic head part for writing

Claims (5)

In a magnetic head using a CPP spin-valve element that includes a nonmagnetic intermediate layer between two or more ferromagnetic layers, and passes a current to the ferromagnetic layer or the nonmagnetic intermediate layer in a plane.
Of the two or more ferromagnetic layers, at least the one layer is, CPP spin-valve, characterized in that a layer containing a Co _X Fe _100-X alloy (where, X = 60-80 [atomic%]) Magnetic head using elements.   The CPP spin valve element further includes an antiferromagnetic layer, and the magnetization direction of any one of the two or more ferromagnetic layers is fixed using the antiferromagnetic layer. A magnetic head using the CPP spin valve element according to 1.   3. A magnetic head using a CPP spin valve element according to claim 1, wherein a NiFe alloy is laminated on the ferromagnetic layer of which the magnetization direction is not fixed in the antiferromagnetic layer.   3. A magnetic head using a CPP spin valve element according to claim 1, wherein Cu is laminated on a ferromagnetic layer whose magnetization direction is not fixed in the antiferromagnetic layer. A magnetic recording / reproducing apparatus using a magnetic head using the CPP spin valve element according to claim 1.

Images