JP2007004901A - Magnetoresistive effect element, thin film magnetic head, magnetic head device and magnetic disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an MR element and a thin film magnetic head in which reproduction output wave distortion is improved. <P>SOLUTION: A first shield layer 31, a second shield layer 33, an MR film 30, and contraction parts 41, 42 are included. The MR film 30 is arranged between the first shield layer 31 and the second shield layer 33. The contraction parts 41, 42 give tensile force T1, T2 in a direction parallel to the film surface to the MR film 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetoresistive element, a thin film magnetic head, a magnetic head device, and a magnetic disk device.

  Magnetoresistive (hereinafter referred to as MR) elements are used in magnetic memory elements, magnetic sensors, or thin film magnetic heads. Among these uses, application to a thin film magnetic head is particularly important. Thin film magnetic heads are required to have high sensitivity and high output in order to cope with the large capacity and miniaturization of hard disk drives (HDDs).

  In the thin film magnetic head, as a response to high sensitivity and high output, the recording element magnetizes the recording layer in the direction perpendicular to the film surface from the in-plane recording element that magnetizes the recording layer of the magnetic recording medium in the longitudinal direction. Corresponding to this, a giant magnetoresistive film (hereinafter referred to as GMR film) and a ferromagnetic tunnel junction film (hereinafter referred to as TMR film) were applied as reproducing elements. Things are being considered.

  As a reproducing element using a GMR film or a TMR film, a CPP (Current Perpendicular to Plane) structure (see Patent Document 1) in which a sense current flows perpendicularly to the film surface is known. When the CPP structure is adopted, the first shield layer and the second shield layer are arranged so that the MR element is sandwiched from both sides of the film thickness, and the first shield layer and the second shield layer are only shielded. It is also used as an electrode for supplying a sense current.

However, it has been found that the linearity of the output waveform may be significantly deteriorated in a thin film magnetic head having a CPP structure. Such deterioration of the linearity of the output waveform is a fatal defect in this type of thin-film magnetic head that must read the data of a magnetic recording medium (magnetic disk) recorded with high density at high speed. It can be.
JP-A-5-275769

  An object of the present invention is to provide an MR element, a thin film magnetic head, a magnetic head device, and a magnetic disk device with improved reproduction output waveform distortion.

1. MR element In order to solve the above-described problem, an MR element according to the present invention includes a first shield layer, a second shield layer, an MR film, and a contraction portion. The MR film is provided between the first shield layer and the second shield layer. The contraction portion applies a tensile force in a direction parallel to the film surface to the MR film.

  As described above, when the tensile force in the direction parallel to the film surface is applied to the MR film via the first shield layer and the second shield layer by the contraction part, the distortion of the reproduced output waveform is eliminated. I understood that I could do it.

  The reason is considered as follows. That is, the GMR film and the TMR film have a multilayer film structure in which films of the order of nm are laminated, and compressive stress is accumulated in the film during the film forming process and the heat treatment process. As a result, the linearity between the applied magnetic field and the output is lost, and the output waveform is distorted. In the present invention, the contraction part gives the MR film a tensile force in a direction parallel to the film surface, so that the compressive stress accumulated in the GMR film and the TMR film is released, and as a result, the output waveform distortion is eliminated. It is thought that.

  Since the MR film is provided between the first shield layer and the second shield layer, it is a reasonable and effective means for applying a tensile force in a direction parallel to the film surface to the MR film. One has a structure having a rigid support body integrated with the first shield layer and the second shield layer, and the contraction portion is in a direction parallel to the film surface of the MR film, And embedding in the support that is present laterally of the first shield layer and the second shield layer.

  The support is typically composed of an inorganic insulating material such as ceramic. Such inorganic insulating materials are very commonly used in thin film magnetic heads and the like.

  A more desirable mode is to arrange the contraction portion side by side with the first shield layer and the second shield layer, that is, to share the same layer. By doing so, the contraction force of the contraction part is reliably and efficiently applied to the first shield layer and the second shield layer via the rigid support, and the tension based on the contraction force of the contraction part is obtained. Force can be effectively applied from the first shield layer and the second shield layer having a large area and volume to the MR film having a small area and volume. The MR film basically has a CPP structure in which a sense current flows in a direction perpendicular to the film surface. However, the MR film having a CIP structure is not excluded.

  In addition, although the structure using a piezoelectric element is also considered as a means to generate | occur | produce a tensile force, since a piezoelectric element is separately formed in this case, a lamination process increases and it leads to a cost increase. On the other hand, the present invention has a merit in terms of process because it is sufficient to apply stress only in the contraction direction and it is not necessary to provide an energization mechanism such as a piezoelectric element.

2. Thin Film Magnetic Head In the thin film magnetic head according to the present invention, the above-described MR element is used as a reproducing element. As a result, the thin film magnetic head having the above-described advantage of the MR element, that is, the effect of improving the reproduction output waveform distortion is obtained.

  The thin film magnetic head according to the present invention includes a recording element as a general configuration. As the recording element, in addition to the in-plane recording element, a perpendicular recording element suitable for high-density recording can be used.

  The present invention further discloses a magnetic head device including the above-described thin film magnetic head and a suspension, and a magnetic disk device including the magnetic head and a magnetic disk.

1. MR Element FIG. 1 is a diagram schematically showing the structure of an MR element according to the present invention, and FIG. 2 is a diagram of the MR element shown in FIG. The illustrated MR element can be used not only as a magnetic storage element or a magnetic sensor, but also as a reproducing element of a thin film magnetic head as will be described later. In FIG. 1 and FIG. 2, in order to display each component clearly, in a range that would not cause misunderstanding, according to a normal drawing display, the portion to be displayed by a dotted line is displayed by a solid line, and It should be noted that the portions that should not be hatched are hatched. The MR element shown in FIGS. 1 and 2 includes a first shield layer 31, an insulating layer 32, a second shield layer 33, and an MR film 30.

The first shield layer 31 and the second shield layer 33 are made of, for example, a NiFe film, and the insulating layer 32 is made of a metal oxide insulating material such as Al ₂ O ₃ or SiO ₂ . The first shield layer 31, the insulating layer 32, the second shield layer 33, and the MR film 30 are covered and supported by the support 1 having rigidity. The support 1 is made of an inorganic insulating material such as Al ₂ O ₃ .

  The MR film 30 is provided between the first shield layer 31 and the second shield layer 33, and is supplied with a sense current using the first shield layer 31 and the second shield layer 33 as electrode layers. The periphery of the MR film 30 is filled with an insulating layer 32. The MR film 30 responds to an applied magnetic field that enters from the magnetosensitive surface 10.

  The contractions 41 and 42 give the MR film 30 tensile forces T1 and T2 in the direction W1 parallel to the film surface. The contracting portions 41 and 42 themselves have a property of contracting as indicated by arrows S1 and S2, for example. In the illustrated embodiment, the contractions 41 and 42 are embedded in the surface of the rigid support 1 at a position away from the first shield layer 31 and the second shield layer 33.

  Therefore, when the contracting portions 41 and 42 contract as indicated by arrows S1 and S2, the first shield layer 31, the insulating layer 32, and the MR film 30 are parallel to the film surface via the rigid support 1. The tensile forces T1 and T2 in the direction W1 are given.

  As the material constituting the contraction portions 41 and 42, a material that is contractible and hardly stretched, and has high adhesion and adhesion to the surrounding layers, that is, the rigid support 1 is used. Any metal / alloy material, inorganic material, or organic material can be used as long as it satisfies the above-described required characteristics. Examples of the metal / alloy material include NiTi and CuZnAl which are a kind of shape memory alloy.

  Examples of organic materials include ethylene copolymers such as polyethylene and ethylene vinyl acetate copolymers, synthetic rubbers such as ethylene propylene rubber, chloroprene rubber and fluoro rubber, polyester resins such as polyethylene terephthalate, and 12-nylon. Such a polyamide resin, a polyvinyl chloride resin, a fluororesin, etc. can be illustrated. These may be used singly or some of them may be blended.

  Further, the contracting portions 41 and 41 may be completely embedded (see FIG. 2) inside the support body 1, or at least a part thereof may be exposed to the outside (see FIG. 3).

  Furthermore, in addition to the circular shape of FIG. 1, the contracting portions 41 and 42 take an arbitrary shape such as an elliptical shape (see FIG. 4), a square shape (see FIG. 5), or a track shape (see FIG. 6). Can do. Although illustration is omitted, each of the storage units 41 and 42 may be divided and provided, or one of the storage units 41 and 42 may be omitted. Further, the contraction parts 41 and 42 may be provided in the first shield layer 31 and the second shield layer 33. 3 to 6, the display method (hatching display or the like) is similar to that in FIGS. 1 and 2.

  One of the rational and effective means for giving the MR film 30 the tensile forces T1 and T2 in the direction W1 parallel to the film surface is as shown in FIGS. 42 is provided inside the support 1 on both sides in the direction W1 parallel to the film surface of the MR film 30.

  As shown in FIGS. 2 and 3, the particularly preferable form is to arrange the contracting portions 41 and 42 side by side with respect to the first shield layer 31 and the second shield layer 33. By doing so, the contraction force of the contraction portions 41 and 42 is reliably and efficiently applied to the first shield layer 31 and the second shield layer 33 via the rigid support 1, and The MR film 30 having a small area and volume can be effectively operated from the first shield layer 31 and the second shield layer 33 having a large area and volume.

  As described above, when the tensile forces T1 and T2 in the direction W1 parallel to the film surface are applied to the MR film 30 by the contracting portions 41 and 42, the distortion of the reproduced output waveform can be eliminated. The reason is as described above.

FIG. 7 is a cross-sectional view showing a specific layer structure of a CPP type MR element. The MR film 30 is a TMR film and includes a free layer 302. One surface of the insulating layer 303 made of an Al ₂ O ₃ layer or the like is adjacent to one surface of the free layer 302, and the other surface of the insulating layer 303 is pinned. One side of layer 304 is adjacent. One surface of the antiferromagnetic layer 305 is adjacent to the other surface of the pinned layer 304. The pinned layer 304 has a magnetization direction fixed in one direction by exchange coupling with the antiferromagnetic layer 305.

  For the layer structure and composition material of the free layer 302, the insulating layer 303, the pinned layer 304, and the antiferromagnetic layer 305, a known technique can be arbitrarily applied. For example, the free layer 302 and the pinned layer 304 are made of, for example, NiFe, NiFeCo, CoFe, or the like, and the antiferromagnetic layer 305 is made of FeMn, MnIr, NiMn, CrMnPt, or the like.

  The first shield layer 31 is adjacent to one surface of the MR film 30 via the plating base layer 306, and the second shield layer 33 is adjacent to the other surface of the MR film 30 via the plating base layer 301. ing. Therefore, a CPP type MR element that allows a sense current to flow in a direction perpendicular to the film surface of the MR film 30 can be obtained.

  On both sides of the MR film 30 in the width direction, magnetic domain control layers 201 and 202 for controlling the magnetic domains of the free layer 302 are disposed. An insulating film 203 is interposed between the magnetic domain control layer 201, the MR film 30 and the plating base film 306, and an insulating film is interposed between the magnetic domain control layer 202, the MR film 30 and the plating base film 306. 204 is interposed.

  The contraction parts 41 and 42 are arranged inside the support 1 so as to be side by side with the first shield layer 31 and the second shield layer 33. As a result, the contraction force of the contraction parts 41 and 42 is applied to the first shield layer 31 and the second shield layer 33 having a large area and volume via the rigid support body 1, and the first It is possible to effectively act on the MR film 30 from the shield layer 31 and the second shield layer 33.

  FIG. 8 is a graph showing the relationship between the externally applied magnetic field and the reproduction output voltage of the reproducing element for a conventional MR element having no contracting portions 41 and 42 in the structure shown in FIG. 8 is a graph showing the relationship between the applied magnetic field and the reproduction output voltage of the reproduction element for the MR element according to the present invention shown in FIG. 7. In the figure, the applied magnetic field (× 79 A / m) is taken on the horizontal axis, and the reproduction output voltage (μV) is taken on the vertical axis.

  Referring to FIG. 8, in the range of applied magnetic field (−300) to (−150) (× 79 A / m), the linearity of the reproduced output voltage with respect to the applied magnetic field is significantly impaired, and the reproduced output waveform is greatly distorted. You can see that it has occurred.

  On the other hand, in the MR element according to the present invention, as shown in FIG. 9, not only the range of the applied magnetic field (−300) to (−150) (× 79 A / m) but also the applied magnetic field as a whole. The linearity of the reproduction output voltage is kept good, and therefore the distortion of the reproduction output waveform is reduced.

2. FIG. 10 is a cross-sectional view of a thin film magnetic head according to the present invention. FIG. 11 shows the thin film magnetic head shown in FIG. 10 on the air bearing surface (ABS) side corresponding to the magnetosensitive surface 10 of FIGS. It is the figure seen from. In the drawing, the dimensional ratios of the respective constituent parts are different from the actual ones, giving priority to the illustration. Further, parts corresponding to the constituent parts appearing in the previously posted drawings are given the same reference numerals. The illustrated thin film magnetic head is a composite head including a slider substrate 11, a recording element 2, and a reproducing element 3. Arrow F1 indicates the direction of air flow that occurs when combined with a magnetic disk.

The slider base 11 is made of Altic or the like having excellent wear resistance. The slider base 11 made of Altic is superior in wear resistance and lubricity as compared with inorganic insulating materials such as Al ₂ O ₃ , but has high conductivity. Therefore, an insulating layer (not shown) such as Al ₂ O ₃ or SiO ₂ is usually attached to the element forming surface of the slider base 11.

The recording element 2 includes a lower magnetic layer 21, a second magnetic layer 22, thin film coils 231 and 232, and a recording gap layer 24, all of which are covered with the protective film 12. The lower magnetic layer 21 is made of a plating layer such as NiFe, CoNiFe, or CoFe, and includes a first magnetic pole layer 210 and a first magnetic pole 211, and a third magnetic layer adjacent to the second shield layer 33. It is formed on the insulating layer 34. The third insulating layer 34 is made of, for example, Al ₂ O ₃ (alumina).

  The first magnetic pole 211 is provided at the end of the first magnetic pole layer 210 on the side facing the recording medium, that is, on the ABS side. The second magnetic layer 22 has a second magnetic pole layer 221 and a second magnetic pole 222. The second magnetic pole layer 221 is formed at a distance from the first magnetic pole layer 210 and is magnetically coupled to the first magnetic pole layer 210 by the rear coupling portion 25 located at the rear. The second magnetic pole layer 221 has a front end adjacent to the second magnetic pole 222 and is made of a magnetic material such as NiFe, CoNiFe, or CoFe. The second magnetic pole 222 is opposed to the first magnetic pole 211 with the same track width through the recording gap layer 24.

  The thin film coils 231 and 232 are configured as plated layers of Cu or the like, and circulate around the rear coupling portion 25. The insulating layers 261 to 265 provide electrical insulation for the thin film coils 231 and 232.

  The reproducing element 3 is constituted by the MR element shown in FIGS. As already described in detail, the MR element includes the first shield layer 31, the second shield layer 33, and the MR film 30. However, it is natural that application to a thin film magnetic head is accompanied by a design modification suitable for it. For example, in comparison with the structure shown in FIG. The structure is different.

  The MR film 30 is provided between the first shield layer 31 and the second shield layer 33, and is supplied with a sense current using the first shield layer 31 and the second shield layer 33 as electrode layers. The periphery of the MR film 30 is filled with an insulating layer 32.

  The contraction parts 41 and 42 give tensile forces T1 and T2 in the direction W1 parallel to the film surface to the MR film 30 by contraction of itself (see FIG. 11). 10 and 11, the rigid support 1 shown in FIGS. 1 to 7 is constituted by the slider base 11, the third insulating film 34, and the protective film 12. The contractions 41 and 42 are embedded in the protective film 12 present on both sides of the first shield layer 31 and the second shield layer 33 in the direction W1 parallel to the film surface of the MR film 30. Therefore, the contraction portions 41 and 42 indirectly apply a tensile force to the MR film 30 via the protective film 12, the first shield layer 31, and the second shield layer 33. 10 and 11 show the in-plane recording element, it may be a perpendicular recording element that magnetizes the recording layer in a direction perpendicular to the film surface.

  Since the thin film magnetic head shown in FIGS. 10 and 11 uses the MR element shown in FIGS. 1 to 7 as the reproducing element 3, the reproducing element 3 will be described with reference to FIGS. All the matters that apply are true.

3. Magnetic Head Device In the present invention, a magnetic head device means a head gimbal assembly (hereinafter referred to as HGA) in which a thin film magnetic head is attached to a gimbal, and a head / arm assembly in which an HGA is attached to an arm ( It is a concept including a head arm assembly (hereinafter referred to as HAA) and a head stack assembly (hereinafter referred to as HSA) in which a plurality of HAAs are stacked.

  FIG. 12 is a front view showing a part of the magnetic head device. The illustrated magnetic head device includes the above-described thin film magnetic head 4 according to the present invention and a head support device 5.

  The head support device 5 supports the thin film magnetic head 4 at one end. The head support device 5 attaches a flexible body 52 made of a metal thin plate to a free end at one end in the longitudinal direction of a support body 51 made of a thin metal plate, and attaches the thin film magnetic head 4 to the lower surface of the flexible body 52. It has a structure. Specifically, the flexible body 52 has a tongue-like piece 521 with the tip of the support body 51 as a free end. For example, a hemispherical load projection 522 is provided on the lower surface of the support 51. The load projection 522 transmits a load force from the free end of the support 51 to the tongue-like piece 521.

  The thin film magnetic head 4 is attached to the lower surface of the tongue-like piece 521 by means such as adhesion, and is supported by the load projection 522 as a fulcrum so that pitch operation and roll operation are allowed.

  The head support device 5 that can be applied to the present invention is not limited to the above-described embodiment, and those that have been proposed or may be proposed in the past can be widely applied. Moreover, what has a conventionally well-known gimbal structure can be used freely.

4). Magnetic Disk Device A magnetic disk device according to the present invention includes a magnetic head device and a magnetic disk. The magnetic head device is the magnetic head device according to the present invention described above. The magnetic disk is used for writing and reading of magnetic recording in cooperation with the magnetic head device.

  FIG. 13 is a perspective view of a magnetic disk device using the magnetic head device shown in FIG. The illustrated magnetic disk device includes a magnetic disk 71 rotatably provided around a shaft 70, a thin film magnetic head 4, and an assembly carriage device for positioning the thin film magnetic head 4 on a track of the magnetic disk 71. It has.

  The assembly carriage device is mainly composed of a carriage 75 that can be rotated about a shaft 74 and an actuator 76 that is, for example, a voice coil motor (VCM) that drives the carriage 75 to rotate.

  A base portion of a plurality of drive arms 77 stacked in the direction of the shaft 74 is attached to the carriage 75, and a head support device 5 on which the thin film magnetic head 4 is mounted is fixed to the tip portion of each drive arm 77. ing. Each head support device 5 is provided at the distal end portion of the drive arm 77 so that the thin film magnetic head 4 at the distal end portion faces the surface of each magnetic disk 71.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.

1 is a plan view schematically showing the structure of an MR element according to the present invention. It is the figure which looked at the MR element shown in FIG. 1 from the magnetosensitive surface side. It is the figure which looked at MR element concerning the present invention from the magnetosensitive surface side. It is a top view which shows typically another example of MR element which concerns on this invention. FIG. 6 is a plan view schematically showing still another example of the MR element according to the present invention. FIG. 6 is a plan view schematically showing still another example of the MR element according to the present invention. It is sectional drawing which shows the specific layer structure of a CPP type MR element. FIG. 8 is a graph showing the relationship between an applied magnetic field and a reproduction output voltage of a reproduction element for a conventional MR element having no contraction in the structure shown in FIG. 7. 8 is a graph showing the relationship between the applied magnetic field and the reproduction output voltage of the reproduction element for the MR element according to the present invention shown in FIG. 7. 1 is a cross-sectional view of a thin film magnetic head according to the present invention. It is the figure which looked at the thin film magnetic head shown in FIG. 10 from the ABS side. It is a front view which shows a part of magnetic head apparatus. FIG. 13 is a perspective view of a magnetic disk device using the magnetic head device shown in FIG. 12.

Explanation of symbols

30 MR film 31 1st shield layer 32 2nd insulating layer 33 2nd shield layer 34 3rd insulating layer 41, 42 Contraction part 1 Rigid support body

Claims (7)

A magnetoresistive effect element including a first shield layer, a second shield layer, a magnetoresistive effect film, and a contraction part,
The magnetoresistive film is provided between the first shield layer and the second shield layer,
The contraction portion gives a tensile force in a direction parallel to the film surface to the magnetoresistive film.
Magnetoresistive effect element. The magnetoresistive effect element according to claim 1,
A rigid support integrated with the first shield layer and the second shield layer;
The contraction is embedded in the support that is present on the side of the first shield layer and the second shield layer in a direction parallel to the film surface of the magnetoresistive film.
Magnetoresistive effect element.   3. The magnetoresistive effect element according to claim 1, wherein the magnetoresistive effect film has a structure in which a sense current flows in a direction perpendicular to a film surface. A thin film magnetic head including a reproducing element,
The reproducing element is a magnetoresistive element according to any one of claims 1 to 3.
Thin film magnetic head.   5. The thin film magnetic head according to claim 4, further comprising a recording element, wherein the recording element is a perpendicular recording element. A magnetic head device including a thin film magnetic head and a suspension,
The thin film magnetic head is the one described in claim 4 or 5,
The suspension supports the thin film magnetic head;
Magnetic head device. A magnetic disk device including a magnetic head device and a magnetic disk,
The magnetic head device is the one described in claim 6, and performs magnetic recording and reproduction with the magnetic disk.
Magnetic disk unit.

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