JP2008078567A - Magnetoresistance effect element, thin film magnetic head, base, wafer, head gimbal assembly, and hard disc device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetoresistance effect element from which good MR characteristics are acquired, without thickening the thickness of the layer consisting of a Heusler alloy formed on a spacer layer and without requiring the rise of temperature of annealing treatment. <P>SOLUTION: The magnetoresistance effect element 4 is laminated so that with respect to a pinned layer 43 of which the magnetization direction is fixed, a nonmagnetic spacer layer 44, a free layer 45 of which the magnetization direction changes according to an external magnetic field, the spacer layer 44 may be located between the pinned layer 43 and the free layer 45. The free layer 45 and an inner layer 43c of the pinned layer includes a Heusler alloy, for example, a film consisting of Co50Mn<SB>y</SB>Si<SB>(50-y)</SB>, and the spacer layer 44 consists of a Cu<SB>(100-x)</SB>Zn<SB>x</SB>alloy. Concentration x of Zn of the spacer layer 44 is 0 at.%<x≤70 at.%, and the thickness of the spacer layer 44 is 0.9 nm or more and 4 nm or less. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetoresistive element, a thin film magnetic head, a substrate, a wafer, a head gimbal assembly, and a hard disk device that are preferably used in a hard disk device.

  A thin film magnetic head having a magnetoresistive element (MR (Magneto-resistance) element) for reading a magnetic signal is used in the hard disk device. In recent years, the recording density of hard disk drives has been increasing, and accordingly, the demand for higher sensitivity and higher output for magnetoresistive elements is also increasing in thin film magnetic heads.

  Conventionally, as a reproducing element of a thin film magnetic head, a CIP-GMR (a giant magnetoresistive effect element) having a nonmagnetic layer between a ferromagnetic layer and a ferromagnetic layer and flowing a sense current in parallel to the film surface is used. Current in Plane-Giant Magneto-resistance) elements have been developed. On the other hand, in order to cope with higher density, the development of a magnetic head using a TMR (Tunnel Magneto-resistance) element that has an insulating layer instead of a non-magnetic layer in the middle and flows a sense current perpendicular to the film surface is also underway. It has been. Further, in a GMR element having a nonmagnetic layer in the middle, development of a magnetic head using a CPP (Current Perpendicular to Plane) -GMR element in which a sense current flows perpendicularly to the film surface as in the case of a TMR element has been underway. The CPP-GMR element has an advantage that it has a low resistance as compared with the TMR element and a high output can be obtained in a narrow track width as compared with the CIP-GMR element.

  In general, a CPP-GMR element has a configuration sandwiched between a lower shield layer and an upper shield layer that also serve as electrode films, and is also called a spin valve film (SV film). This CPP-GMR element has a columnar shape of a desired size, and includes a pinned layer (magnetization pinned layer) which is a ferromagnetic layer whose magnetization direction is fixed, and a ferromagnetic layer whose magnetization direction changes according to an external magnetic field. In this structure, a nonmagnetic spacer layer is sandwiched between a certain free layer. The pinned layer has a magnetization direction fixed by being provided on the antiferromagnetic layer. Recently, the pinned layer has a ferromagnetic layer (inner layer) / nonmagnetic metal layer (nonmagnetic intermediate layer) / ferromagnetic layer (outer layer) three-layer structure (synthetic pinned) instead of a ferromagnetic single layer structure. CPP-GMR elements have been developed that provide strong exchange coupling between the two ferromagnetic layers to effectively increase the exchange coupling force from the antiferromagnetic layer.

A hard magnetic film (hard bias film) made of CoPt or CoCrPt is provided around the CPP-GMR element via an insulating film such as Al ₂ O ₃ . This hard bias film is a magnetic domain control film of a free layer located on the side of the CPP-GMR element in the track width direction. A cap layer and a buffer layer are provided on the upper and lower ends of the CPP-GMR element, respectively, and are sandwiched between the upper shield layer and the lower shield layer.

  As described in Patent Document 1, it has been found that in a CPP-GMR element, a large MR (magnetic resistance) change rate of 10% or more can be obtained by using a Heusler alloy for a free layer or a pinned layer. . That is, it has been found that the MR change increases as the spin polarizability of the free layer and the pinned layer increases, and that the MR change rate increases by using a material having a high spin polarizability for the free layer and the pinned layer. It has been found that a material that realizes a half metal that is a magnetic substance having a spin polarizability of 100% or close to it is a Heusler alloy. In this way, by using a Heusler alloy instead of a CoFe alloy or NiFe alloy for the free layer and the pinned layer, the MR change rate increases, leading to an increase in output.

In addition, as shown in Patent Documents 1 and 2, when Cu is used as the spacer layer (nonmagnetic layer) sandwiched between the pinned layer and the free layer, it has been found that the MR characteristics are good. Yes.
JP 2003-218428 A Japanese Patent Laid-Open No. 10-143822 JP-A-8-250366 JP 2005-116701 A

  As described above, it has been found that the use of Heusler alloy for the free layer and the pinned layer and the use of Cu for the spacer layer in contact with the free layer are preferable in terms of MR characteristics. However, if a layer made of Heusler alloy (which may be a free layer or an inner layer of a pinned layer) is formed on a spacer layer made of Cu, the Heusler alloy grows well. Therefore, there is a problem that the original film characteristics (for example, MR ratio) cannot be exhibited. In order to solve this problem, it is necessary to form a Heusler alloy film thicker than the conventional one on the spacer layer made of Cu, and to raise the temperature of the annealing process for ordering Heusler. In that case, however, the MR element becomes large, which hinders the miniaturization and high density of the thin film magnetic head. In addition, since the annealing temperature becomes high, there are inconveniences such as deterioration of the characteristics of the thin film magnetic head due to heat and the necessity of preparing an apparatus with higher heat resistance as the annealing equipment.

  On the other hand, in Patent Documents 3 and 4, a layer made of Cr, V, Nb, Mo, Ta, W, or an alloy thereof having a body-centered cubic lattice structure that is structurally compatible with the Heusler alloy is provided under the Heusler alloy layer. It is disclosed that a good film growth of the Heusler alloy layer can be realized by forming. In these configurations, it is not necessary to increase the thickness of the Heusler alloy film, and it is not necessary to increase the annealing temperature. However, the effect on MR characteristics by using Cu as the spacer layer cannot be exhibited.

  Accordingly, an object of the present invention is to provide a magnetoresistive effect element and a thin film that do not require an increase in the thickness of the layer containing the Heusler alloy, do not need to increase the temperature of the annealing process, and can obtain a good effect on the MR characteristics. An object is to provide a magnetic head, a substrate, a wafer, a head gimbal assembly, and a hard disk device.

  A feature of the present invention is that a pinned layer whose magnetization direction is fixed, a nonmagnetic spacer layer, and a free layer whose magnetization direction changes according to an external magnetic field, the spacer layer is between the pinned layer and the free layer. In the magnetoresistive effect element laminated so as to be positioned, at least one of the free layer and the pinned layer includes a Heusler alloy, and the spacer layer is formed of a CuZn alloy. Specifically, among the free layer and the pinned layer, at least a layer formed by film growth on the spacer layer contains a Heusler alloy.

The spacer layer is preferably made of Cu _(100-x) Zn _x (0 at.% <X ≦ 70 at.%). The thickness of the spacer layer is preferably 0.9 nm or more and 4 nm or less.

  According to this configuration, even if the layer (free layer or pinned layer) formed on the spacer layer is relatively thin and the annealing temperature is relatively low, the Heusler alloy can be sufficiently ordered and a high MR ratio can be obtained. Furthermore, since a CuZn alloy containing Zn close to Cu is used as the spacer layer, good MR characteristics can be obtained.

  The thin film magnetic head of the present invention has the magnetoresistive element having the above-described configuration, and the substrate of the present invention has the thin film magnetic head. The wafer of the present invention is provided with at least one thin-film magnetic head having the above-described configuration, which is used for manufacturing a substrate having the above-described configuration. Further, the head gimbal assembly of the present invention includes the base body having the above-described structure, and includes a slider disposed to face the recording medium and a suspension that elastically supports the slider. The hard disk device of the present invention includes the base body having the above-described configuration, supports a slider disposed opposite to the disk-shaped recording medium that is driven to rotate, supports the slider, and positions the slider with respect to the recording medium. A positioning device.

  According to the present invention, since it is not necessary to increase the thickness of the layer (free layer or pinned layer) formed on the spacer layer, the MR element can be miniaturized, contributing to the miniaturization and high density of the thin film magnetic head. In addition, since the Heusler alloy can be sufficiently ordered even if the annealing temperature is not too high, the deterioration of the characteristics of the thin film magnetic head due to heat can be suppressed, and the equipment and process for annealing can be simplified. . Moreover, since a CuZn alloy containing Zn close to Cu is used as the spacer layer, good MR characteristics equivalent to or higher than Cu or equivalent to Cu can be secured.

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

[Configuration of thin film magnetic head]
FIG. 1 conceptually shows a cross-sectional view of the main part of a thin film magnetic head according to an embodiment of the present invention.

  The thin film magnetic head 1 according to this embodiment includes a substrate 11, a reproducing unit 2 for reading and a recording unit 3 for writing on a recording medium (not shown) formed on the substrate 11.

The substrate 11 is made of Al ₂ O ₃ .TiC (Altic) having excellent wear resistance. A base layer 12 made of alumina is formed on the upper surface of the substrate 11, and the reproducing unit 2 and the recording unit 3 are laminated thereon.

  A lower shield layer 13 made of a magnetic material such as permalloy (NiFe) is formed on the base layer 12. A CPP-GMR element (hereinafter simply referred to as “MR element”) 4 which is a magnetoresistive effect element is provided at the end on the medium facing surface S side above the lower shield layer 13, and one end of the CPP-GMR element is called the medium facing surface S. It is formed so as to be exposed. A first upper shield layer 15 made of a magnetic material such as permalloy is formed on the MR element 4. The lower shield layer 13, the MR element 4, and the first upper shield layer 15 constitute the reproducing unit 2. An insulating layer 16 a is mainly formed in a portion where the MR element 4 does not exist between the lower shield layer 13 and the first upper shield layer 15. The MR element 4 is also referred to as an SV film (spin valve film).

  A lower magnetic pole layer 17 made of a magnetic material such as permalloy or CoNiFe is formed on the first upper shield layer 15 via an insulating layer 16b. The lower magnetic pole layer 17 also functions as a second upper shield layer of the MR element 4 in addition to the function as the lower magnetic pole layer of the recording unit 3.

  An upper magnetic pole layer 19 is formed on the lower magnetic pole layer 17 that also functions as a second upper shield layer via a recording gap layer 18 made of a nonmagnetic material such as Ru or alumina. The recording gap layer 18 is formed at the end on the medium facing surface S side so that one end is exposed to the medium facing surface S. As the material of the upper magnetic pole layer 19, a magnetic material such as permalloy or CoNiFe is used. The lower magnetic pole layer (second upper shield layer) 17 and the upper magnetic pole layer 19 are magnetically connected by the connecting portion 21 to form one magnetic circuit as a whole.

  Between the lower magnetic pole layer 17 and the upper magnetic pole layer 19, between the medium facing surface S and the connection portion 21, coils 20a and 20b made of a conductive material such as copper are formed in two layers. Each of the coils 20 a and 20 b supplies magnetic flux to the lower magnetic pole layer 17 and the upper magnetic pole layer 19, and is formed so that the planar shape is a spiral around the connection portion 21. The coils 20a and 20b are insulated from the surroundings by an insulating layer. Although the two-layer coils 20a and 20b are shown in the present embodiment, the present invention is not limited to this, and may be one layer or three or more layers.

  The overcoat layer 22 is provided so as to cover the upper magnetic pole layer 19 and protects the above-described structure. As a material of the overcoat layer 22, an insulating material such as alumina is used.

[Configuration of MR element]
Next, the MR element (SV film) 4 will be described in detail with reference to FIG. 2 which is a view seen from the medium facing surface S side.

  As described above, the MR element 4 is sandwiched between the lower shield layer 13 and the upper shield layer 15, and includes a buffer layer 41, an antiferromagnetic layer 42, a pinned layer 43, a spacer layer 44, a free layer. 45 and the cap layer 46 are laminated in this order from the lower shield layer 13 side. In the example shown in FIG. 2, the pinned layer 43 has a configuration in which a nonmagnetic intermediate layer 43b is sandwiched between an outer layer 43a and an inner layer 43c each made of a ferromagnetic material. Such a pinned layer 43 is called a synthetic pinned layer. The outer layer 43 a is provided in contact with the antiferromagnetic layer 42, and the inner layer 43 c is provided in contact with the spacer layer 44. An example of the material and thickness of each layer is shown in Table 1. The description such as “Co90Fe10” in Table 1 is a more detailed expression of “CoFe” etc., and indicates the atomic fraction of each component in percentage, for example, a layer containing 90% Co and 10% Fe It means that.

  The lower shield layer 13 and the upper shield layer 15 also serve as electrodes. A sense current flows through the MR element 4 through the lower shield layer 13 and the upper shield layer 15 in a direction perpendicular to the film surface. The lower shield layer 13 and the upper shield layer 15 are made of a NiFe film of about 2 μm or less.

  The buffer layer 41 is made of a laminated film of Ta / NiCr or the like, which is selected as a material for a combination that provides good exchange coupling between the antiferromagnetic layer 42 and the outer layer 43a of the pinned layer 43. In this specification, “/” indicating a multilayer film structure means that the material on the left side of “/” is a lower layer than the material on the right side, that is, a layer formed first. The antiferromagnetic layer 42 plays a role of fixing the magnetization direction of the pinned layer 43, and is composed of, for example, an IrMn film of 7.0 nm.

The pinned layer 43 is formed as a magnetic layer, and has a configuration in which the outer layer 43a, the nonmagnetic intermediate layer 43b, and the inner layer 43c are laminated in this order, as described above. The outer layer 43a has a magnetization direction fixed with respect to an external magnetic field by the antiferromagnetic layer 42, and is composed of, for example, a Co70Fe30 film having a thickness of 5.0 nm. The nonmagnetic intermediate layer 43b is made of a Ru film having a thickness of 0.4 to 0.8 nm, for example. The inner layer 43c is a ferromagnetic layer containing at least a portion Heusler alloy, for example, a layer made of _{Co70Fe30 / Co50Mn y Si (50-} y) / Co30Fe70. Here, y = 20-30 at. %. In such a synthetic pinned layer, the magnetic moments of the outer layer 43a and the inner layer 43c cancel each other, the entire leakage magnetic field is suppressed, and the magnetization direction of the inner layer 43c is firmly fixed.

The spacer layer 44 is made of a nonmagnetic material. The spacer layer 44 of the present invention is made of, for example, Cu _(100-x) Zn _{x having a} thickness of 2.2 nm. Here, 0 at. % <X ≦ 70 at. %, Preferably x = 36.1-59.1 at. %. The effect of using Cu _(100-x) Zn _x as the spacer layer 44 will be described later.

The magnetization direction of the free layer 45 changes according to the external magnetic field. Free layer 45 is a multilayer structure comprising a layer containing at least a portion Heusler alloy, such as _{Co70Fe30 / Co50Mn y Si (50-} y).

The Heusler alloy layer has a composition formula of X ₂ YZ or XYZ (where X is one of Cu, Co, Ni, Rh, Pt, Au, Pd, Ir, Ru, Ag, Zn, Cd, Fe or Two or more elements, Y is Mn, Fe, Ti, V, Zr, Nb, Hf, Ta, Cr, Co, Ni, one or more elements, Z is Al, Sn, In, Sb, 1 or 2 or more elements among Ga, Si, Ge, Pb, and Zn).

  The cap layer 46 is provided for preventing deterioration of the MR element 4 and is made of Ru having a thickness of 10.0 nm, for example.

Insulation is provided on both sides (left and right sides in FIG. 2) of the MR element 4 in the track width direction (in-plane direction of each layer constituting the MR element 4 in a plane parallel to the medium facing surface S (see FIG. 1)). A hard bias film 48 is provided via the film 47. The hard bias film 48 makes the free layer 45 a single magnetic domain by applying a bias magnetic field in the track width direction to the free layer 45. For the hard bias film 48, for example, a hard magnetic material such as CoPt or CoCrPt is used. The insulating film 47 is for preventing the sense current from leaking to the hard bias film 48, and can be formed of an oxide film such as Al ₂ O ₃ , for example. The insulating film 47 may be a part of the insulating layer 16a.

[Material of spacer layer and layer containing Heusler alloy]
Here, the most characteristic structure in this embodiment, as the ferromagnetic layer formed on the spacer layer 44, for example, such as _{Co70Fe30 / Co50Mn y Si (50-} y), with using a layer containing a Heusler alloy In other words, a Cu _(100-x) Zn _x film is used as the spacer layer 44. This will be described below. In the following description, an example in which the free layer 45 is formed on the spacer layer 44 will be described. However, when the pinned layer 43 is formed on the spacer layer 44, the free layer 45 described below is used as the pinned layer. 43 may be replaced with the inner layer 43c.

  As described in Patent Document 1, it is preferable to use a Heusler alloy film as the free layer 45 and the pinned layer 43 and a Cu film as the spacer layer 44 in consideration of characteristics such as the MR ratio in the MR element 4. I know. However, when the free layer 45 made of Heusler alloy is formed on the spacer layer 44 made of Cu, the film cannot be grown satisfactorily, and as a result, the characteristics of the MR element 4 may be deteriorated. Therefore, in order to ensure good characteristics of the MR element 4, measures such as increasing the thickness of the free layer 45 made of Heusler alloy and increasing the temperature of the annealing treatment for ordering the Heusler alloy are taken. It was done. However, these measures have led to an increase in the size of the MR element 4 and have hindered miniaturization and high density of the thin film magnetic head. Further, when the annealing temperature is higher than 300 ° C., there is a risk that the characteristics of the thin film magnetic head may be adversely affected by heat, and the annealing equipment and processes become more complicated as the annealing temperature increases.

  Considering the reason why the Heusler alloy cannot grow well on the Cu film, the difference in structure between the two can be considered. That is, it is considered that the Cu film has a face-centered cubic lattice structure (fcc structure), whereas the Heusler alloy has a body-centered cubic lattice structure (bcc structure). Therefore, in Patent Documents 3 and 4, a film made of Cr, V, Nb, Mo, Ta, W, or an alloy thereof having a body-centered cubic lattice structure is used as the spacer layer 44 instead of the Cu film. According to this configuration, since the free layer 45 made of Heusler alloy is formed on the spacer layer 44 having the same kind of structure (body-centered cubic lattice structure), the film growth is good, and the spacer layer is more than necessary. There is no need to increase the thickness of 44 or raise the temperature of the annealing process. However, since a particularly good Cu film is not used as the spacer layer 44, it cannot be said that the characteristics such as the MR ratio are optimal.

Therefore, the present applicant considered that a material having a body-centered cubic lattice structure similar to the Heusler alloy and equivalent to Cu was used as the spacer layer 44. As a result, it has been found that it is effective to use an alloy in which a metal (Zn) close to Cu is mixed with Cu, specifically, Cu _(100-x) Zn _x as the spacer layer 44. This will be demonstrated below.

(Experiment 1)
The applicant has the configuration described in Table 1 above, that is, the example of the present invention in which the spacer layer 44 is made of Cu _(100-x) Zn _x (x = 46 at.%), And the configuration described in Table 2. That is, with respect to the conventional example in which the spacer layer 44 is made of Cu, the thickness of the spacer layer 44 was changed, and the MR ratio of each MR element 4 was obtained. The results are shown in Table 3 and FIG. In this embodiment and the conventional example, the thickness of the Heusler alloy film of the free layer 45 is 3.0 nm, and the annealing temperature for ordering the Heusler alloy is 300 ° C.

Referring to Table 3 and FIG. 3, the conventional example using Cu as the spacer layer 44 and the example using Cu _(100-x) Zn _x (x = 46 at.%) As the spacer layer 44 are as follows. In any case, the MR ratio can be exhibited when the thickness of the spacer layer 44 is larger than 5 mm (0.5 nm), and when the film thickness is about 20 to 25 mm (2.0 to 2.5 nm), the highest MR ratio is obtained. can get. In particular, in this embodiment, when the thickness of the spacer film 44 is 9 mm (0.9 nm) or more, an MR ratio higher than the highest MR ratio (about 10.2%) of the conventional example can be obtained. As can be seen from Table 3 and FIG. 3, according to the present embodiment, a higher MR ratio can be realized with the spacer layer 44 thinner than the conventional one. Accordingly, when the thickness of the Heusler alloy film of the free layer 45 is the same and the spacer layer 44 has a general thickness (at least larger than 5 mm), the present embodiment is higher than the conventional example. It is clear that MR ratio can be obtained.

(Experiment 2)
In the embodiment of the present invention having the configuration shown in Table 1 and the conventional example having the configuration shown in Table 2, the thickness of the Heusler alloy film of the free layer 45 is kept constant at 30 mm (3.0 nm), and the thickness of the spacer layer 44 is Similarly, the temperature was kept constant at 30 mm (3.0 nm), the temperature of annealing treatment for ordering the Heusler alloy was changed, and the respective MR ratios were obtained. The results are shown in Table 4 and FIG.

Referring to Table 4 and FIG. 4, in the case of the conventional example using Cu as the spacer layer 44, the annealing temperature is set to about 300 ° C. or higher (at least higher than 270 ° C.) in order to exhibit the MR ratio. There is a need to. On the other hand, in the embodiment using Cu _(100-x) Zn _x (x = 46 at.%) As the spacer layer 44, if the annealing temperature is about 270 ° C. (at least higher than 250 ° C.). MR ratio can be achieved (if temperature). That is, according to the present invention, it is considered that a sufficiently ordered state of the Heusler alloy can be obtained without increasing the temperature of the annealing treatment, thereby obtaining a high MR ratio. Thus, according to the present invention, the annealing temperature can be set lower than in the prior art, so that adverse effects on the characteristics of the thin film magnetic head due to heat can be suppressed.

(Experiment 3)
Next, the structure shown in Table 1, Heusler alloys _{(Co50Mn y Si (50-y} )) of the free layer 45 to a thickness of film 10Å (1.0nm), 30Å (3.0nm ), 60Å (6.0nm The thickness of the spacer layer 44 made of Cu _(100-x) Zn _x (x = 46 at.%) Of each of the three types of MR elements set in ₍₁ ) is set in the range of 0 to 50 mm (0 to 5.0 nm). The MR ratio was obtained by changing the value. The results when the thickness of the Heusler alloy film of the free layer 45 is 10 mm (1.0 nm) are shown in Table 5 and FIG. 5, the results when the thickness is 30 mm (3.0 nm) are shown in Table 6 and FIG. The result in the case of 0.0 nm) is shown in Table 7 and FIG.

Referring to Table 5 and FIG. 5, when the thickness of the Heusler alloy film of the free layer 45 is 10 mm (1.0 nm), the thickness of the spacer layer 44 of this example is 7 to 44 mm (0.7 to It can be seen that an MR ratio higher than the highest MR ratio of the conventional example (about 6.1%) can be obtained at about 4.4 nm). Further, referring to Table 6 and FIG. 6, when the thickness of the Heusler alloy film of the free layer 45 is 30 mm (3.0 nm), the thickness of the spacer layer 44 of this embodiment is 9 to 40 mm (0. It can be seen that an MR ratio higher than the highest MR ratio (about 10.2%) of the conventional example can be obtained at about 9 to 4.0 nm). When Table 7 and FIG. 7 are seen, when the thickness of the Heusler alloy film of the free layer 45 is 60 mm (6.0 nm), the thickness of the spacer layer 44 of this embodiment is 9 to 41 mm (0. It can be seen that an MR ratio higher than the highest MR ratio (about 12.2%) of the conventional example can be obtained at about 9 to 4.1 nm). From the above, at least in the range where the thickness of the spacer layer 44 is 9 to 40 mm (0.9 to 4.0 nm), the present invention uses Cu as the spacer layer 44 regardless of the thickness of the free layer 45. It can be seen that a larger MR ratio can be obtained compared to the conventional example. Here, 9 mm (0.9 nm) set as the lower limit value of the film thickness of the spacer layer 44 is the minimum film thickness necessary for the growth of Cu _(100-x) Zn _x (this is the structure of the free layer 45). (It is a value determined independently of). Further, 40 mm (4.0 nm) set as the upper limit value of the film thickness of the spacer layer 44 is a spin scattering length of Cu _(100-x) Zn _x (a length inherent to the material capable of exhibiting the MR ratio _). It is a value determined independently of the structure of 45).

(Experiment 4)
In the configuration shown in Table 1, the MR ratio was determined by changing the x value of Cu _(100-x) Zn _x constituting the spacer layer 44, that is, the Zn concentration (ratio). At this time, the thickness of the Heusler alloy film of the free layer 45 is fixed to 30 mm (3.0 nm), and the thickness of the spacer layer 44 is 20 mm (2.0 nm), 25 mm (2.5 nm), 30 mm (3.0 nm). ). The results are shown in Table 8 and FIG.

Here, referring to Table 6 and FIG. 6, in the conventional example using Cu as the spacer layer 44, the thickness of the Heusler alloy layer of the free layer 45 is 30 mm (3.0 nm), and the thickness of the spacer layer 44 is MR ratio is 10.2% at 20 mm (2.0 nm), 10.1% at 25 mm (2.5 nm), and 9.5 at 30 mm (3.0 nm). %. Therefore, according to Table 8 and FIG. 8, the MR ratio higher than that of the conventional example can be obtained in this embodiment. % <Zn ≦ 70 at. %. This Zn concentration range includes a range (36.1 to 59.1 at.%) In which Cu _(100-x) Zn _x takes a body-centered cubic lattice structure. This can be confirmed by the phase diagram of CuZn.

According to the experiments described above, the configuration of the present invention in which the spacer layer 44 is made of Cu _(100-x) Zn _x has the same thickness as that of the conventional configuration in which the spacer layer 44 is made of Cu. Therefore, it can be seen that a relatively thin spacer layer 44 provides a sufficient MR ratio according to the present invention. This is effective for miniaturization and high density of the thin film magnetic head.

  Further, according to the experiments described above, in the configuration of the present invention, the Heusler alloy film having the same thickness can be ordered at a lower annealing temperature than in the conventional configuration, thereby obtaining a higher MR ratio. I understand. According to the present invention, since annealing can be performed at a relatively low temperature, the characteristics of the thin film magnetic head can be prevented from being deteriorated by heat, and the equipment and process for annealing are simplified.

Further, according to the above-described experiments, the structure of the present invention, particularly the thickness of the spacer layer 44 made of Cu _(100-x) Zn _x, is 9 to 40 mm (0. 0 ₎ regardless of the thickness of the Heusler alloy of the free layer 45. It can be seen that the MR ratio higher than the conventional one can be realized in the configuration within the range of 9 to 4.0 nm. Further, according to each experiment described above, the Zn concentration (ratio) of Cu _(100-x) Zn _x constituting the spacer layer 44 is 0 at. % <Zn ≦ 70 at. %, An MR ratio higher than the conventional one can be obtained and it can be seen that it is very preferable.

The above description relates to an example in which the pinned layer 43, the spacer layer 44, and the free layer 45 are stacked in this order. Conversely, the free layer 45, the spacer layer 44, and the pinned layer 43 are stacked in this order. Sometimes formed. In that case, the inner layer 43c of the pinned layer 43 formed by growing the film on the spacer layer 44 contains a Heusler alloy. However, since the spacer layer 44 is made of Cu _(100-x) Zn _x , the Heusler The alloy grows well on the spacer layer 44, and the same effect as described above can be obtained.

[Head gimbal assembly including thin film magnetic head and hard disk drive]
A plurality of thin film magnetic heads 1 of the present invention are formed side by side on a single wafer. FIG. 9 shows a schematic plan view of a wafer on which a large number of structures (substrates) including the thin film magnetic head shown in FIG. 1 are formed.

  The wafer 100 is partitioned into a plurality of head element assemblies 101. The head element assembly 101 includes a plurality of head elements 102 and serves as a unit of work for polishing the medium facing surface S of the thin film magnetic head 1 (see FIG. 1). Cutting margins (not shown) for cutting are provided between the head element assemblies 101 and between the head elements 102, respectively. The head element 102 is a structure (base) including the configuration of the thin film magnetic head 1, and necessary processing such as polishing for forming the medium facing surface S is performed to form the thin film magnetic head 1. This polishing process is generally performed with a plurality of head elements 102 cut out in a row.

  Next, a head gimbal assembly and a hard disk device including the thin film magnetic head of the present invention will be described. First, the slider 210 included in the head gimbal assembly will be described with reference to FIG. In the hard disk device, the slider 210 is arranged to face a hard disk that is a disk-shaped recording medium that is driven to rotate. The slider 210 includes the thin-film magnetic head 1 obtained from the head element 102 (see FIG. 9), and the air bearing surface 200 is formed on the medium facing surface S facing the hard disk, and has a substantially hexahedral shape as a whole. Yes. When the hard disk rotates in the z direction in FIG. 10, lift is generated in the slider 210 downward in the y direction by the air flow passing between the hard disk and the slider 210. The slider 210 floats from the surface of the hard disk by this lifting force. The x direction in FIG. 10 is the track crossing direction of the hard disk. On the air outflow side end surface 211 of the slider 210, electrode pads for signal input and output to the reproducing unit 2 and the recording unit 3 (see FIG. 1) are formed. This surface corresponds to the upper end surface in FIG.

  Next, the head gimbal assembly 220 will be described with reference to FIG. The head gimbal assembly 220 includes a slider 210 and a suspension 221 that elastically supports the slider 210. The suspension 221 includes, for example, a leaf spring-like load beam 222 formed of stainless steel, a flexure 223 that is provided at one end of the load beam 222 and is joined to the slider 210 to give the slider 210 an appropriate degree of freedom. And a base plate 224 provided at the other end of the beam 222. The base plate 224 is attached to an arm 230 of an actuator for moving the slider 210 in the track crossing direction x of the hard disk 262. The actuator includes an arm 230 and a voice coil motor that drives the arm 230. In the flexure 223, a part to which the slider 210 is attached is provided with a gimbal part for keeping the posture of the slider 210 constant.

  The head gimbal assembly 220 is attached to the arm 230 of the actuator. A structure in which the head gimbal assembly 220 is attached to one arm 230 is called a head arm assembly. Further, a head gimbal assembly 220 attached to each arm of a carriage having a plurality of arms is called a head stack assembly.

  FIG. 11 shows an example of a head arm assembly. In this head arm assembly, a head gimbal assembly 220 is attached to one end of the arm 230. A coil 231 that is a part of the voice coil motor is attached to the other end of the arm 230. A bearing portion 233 attached to a shaft 234 for rotatably supporting the arm 230 is provided at an intermediate portion of the arm 230.

  Next, an example of the head stack assembly and the hard disk device will be described with reference to FIGS. FIG. 12 is an explanatory view showing the main part of the hard disk device, and FIG. 13 is a plan view of the hard disk device. The head stack assembly 250 has a carriage 251 having a plurality of arms 252. A plurality of head gimbal assemblies 220 are attached to the plurality of arms 252 so as to be arranged in the vertical direction at intervals. A coil 253 that is a part of the voice coil motor is attached to the carriage 251 on the opposite side of the arm 252. The head stack assembly 250 is incorporated in a hard disk device. The hard disk device has a plurality of hard disks (magnetic recording media) 262 attached to a spindle motor 261. For each hard disk 262, two sliders 210 are arranged so as to face each other with the hard disk 262 interposed therebetween. Further, the voice coil motor has permanent magnets 263 arranged at positions facing each other with the coil 253 of the head stack assembly 250 interposed therebetween.

  The head stack assembly 250 and the actuator excluding the slider 210 support the slider 210 and position it relative to the hard disk 262.

  In the hard disk device, the slider 210 is moved with respect to the hard disk 262 by moving the slider 210 in the track crossing direction of the hard disk 262 by the actuator. The thin film magnetic head 1 included in the slider 210 records information on the hard disk 262 by the recording unit 3 and reproduces information recorded on the hard disk 262 by the reproducing unit 2.

  The thin film magnetic head 1 is not limited to the above-described form, and various modifications can be made. For example, in the embodiment described above, the thin film magnetic head 1 having the structure in which the MR element 4 for reading is formed on the substrate 11 side and the inductive electromagnetic transducer for writing is stacked thereon has been described. May be reversed. In the above-described embodiment, the case where both the MR element 4 and the inductive electromagnetic conversion element are included has been described as an example, but only the MR element 4 may be included.

1 is a cross-sectional view of a main part of a thin film magnetic head according to an embodiment of the present invention. FIG. 2 is a diagram when the MR element shown in FIG. 1 is viewed from the medium facing surface side. 3 is a graph showing the relationship between the film thickness of the spacer layer and the MR ratio, showing the results of Experiment 1 for examining the characteristics of the MR element shown in FIG. 6 is a graph showing the relationship between the annealing temperature and the MR ratio, showing the results of Experiment 2 for examining the characteristics of the MR element shown in FIG. 6 is a graph showing the relationship between the spacer layer thickness and the MR ratio when the thickness of the Heusler alloy film of the free layer is 10 mm, showing the results of Experiment 3 for examining the characteristics of the MR element shown in FIG. 6 is a graph showing the relationship between the spacer layer thickness and the MR ratio when the thickness of the Heusler alloy film of the free layer is 30 mm, showing the results of Experiment 3 for examining the characteristics of the MR element shown in FIG. 6 is a graph showing the relationship between the spacer layer thickness and the MR ratio when the thickness of the Heusler alloy film of the free layer is 60 mm, showing the results of Experiment 3 for examining the characteristics of the MR element shown in FIG. It is a graph which shows the result of the experiment 4 for investigating the characteristic of MR element shown in FIG. 1, and shows the relationship between Zn density | concentration in CuZn of a spacer layer, and MR ratio. It is a top view of an example of the wafer in which the thin film magnetic head shown in FIG. 1 was formed. FIG. 2 is a perspective view of an example of a slider including the thin film magnetic head shown in FIG. 1. FIG. 11 is a perspective view of a head gimbal assembly including the slider shown in FIG. 10. It is a principal part side view of the hard disk drive containing the head gimbal assembly shown in FIG. FIG. 12 is a plan view of a hard disk device including the head gimbal assembly shown in FIG. 11.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thin film magnetic head 2 Reproduction | regeneration part 3 Recording part 4 MR element (magnetoresistance effect element)
Reference Signs List 13 Lower shield layer 15 Upper shield layer 41 Buffer layer 42 Antiferromagnetic layer 43 Pinned layer 43a Outer layer 43b Nonmagnetic intermediate layer 43c Inner layer 44 Spacer layer 45 Free layer 46 Cap layer 47 Insulating film 48 Hard bias film

Claims (9)

A pinned layer whose magnetization direction is fixed, a nonmagnetic spacer layer, and a free layer whose magnetization direction changes according to an external magnetic field are positioned between the pinned layer and the free layer. In the magnetoresistive effect element laminated on
At least one of the free layer and the pinned layer includes a Heusler alloy,
The spacer layer is made of a CuZn alloy. A magnetoresistive effect element.   2. The magnetoresistive effect element according to claim 1, wherein at least one of the free layer and the pinned layer formed by film growth on the spacer layer includes a Heusler alloy. The magnetoresistive element according to claim 1, wherein the spacer layer is made of a Cu _(100-x) Zn _x alloy (0 at.% <X ≦ 70 at.%).   The magnetoresistive effect element according to any one of claims 1 to 3, wherein the spacer layer has a thickness of 0.9 nm or more and 4 nm or less.   A thin film magnetic head comprising the magnetoresistive element according to claim 1.   A substrate having the thin film magnetic head according to claim 5.   A wafer provided with at least one thin film magnetic head, which is used for manufacturing the substrate according to claim 6. A slider including the substrate according to claim 6 and disposed to face the recording medium;
A suspension for elastically supporting the slider;
A head gimbal assembly. A slider that includes the substrate according to claim 6 and that is disposed to face a disk-shaped recording medium that is rotationally driven;
A positioning device that supports the slider and positions the slider relative to the recording medium;
A hard disk device.

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