JP2006012396A - Magnetic head for perpendicular magnetic recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic head for perpendicular magnetic recording which can prevent the occurrence of pole-erasure sufficiently in the recording of a recording medium. <P>SOLUTION: In the magnetic head 2 for perpendicular magnetic recording which has a medium opposing plane S arranged opposing to a recording plane 3a of s recording medium 3, in which magnetic fluxes are discharged toward the recording plane 3a of the recording medium 3 and magnetic information is recorded in the magnetic medium 3, the head is provided with a magnetic pole 21 discharging magnetic fluxes toward the recording plane 3a of the recording medium 3 and return yokes 16, 17 of which the one end is connected to the magnetic pole 21 and the other end is arranged opposing to the recording plane 3a of the recording medium 3, materials constituting the magnetic pole 21 has magnetostriction constant of 10×10<SP>-6</SP>or more to 60×10<SP>-6</SP>, and P expressed by the equation P=Hk/(λ×σ) is 0.2 or more to less than 20. Where, Hk is anisotropic magnetic field (A/m), σ is stress (MPa), λ is magnetostriction constant. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic head for perpendicular magnetic recording used in a perpendicular magnetic recording type magnetic recording apparatus.

  In a magnetic recording apparatus, in order to realize a high density recording medium, a perpendicular magnetic recording system that records magnetic information in a direction perpendicular to the recording surface of the recording medium is employed. For this purpose, a magnetic head for perpendicular magnetic recording is used.

  Perpendicular magnetic recording media include two-layer recording media having a recording layer and a soft magnetic backing layer, and single-layer recording media having no backing layer. When used, it is necessary to perform magnetic recording on the recording medium using a magnetic head having a magnetic pole and a return yoke.

  On the other hand, in order to improve the recording density, in addition to the linear recording density in the recording medium, it is desired to improve the track density by reducing the width of the pole portion. However, when the pole portion is narrowed, residual magnetization is generated in the magnetic pole due to the effect of shape anisotropy. Therefore, when magnetic information is recorded on the recording medium using a magnetic head, the residual magnetic field caused by the residual magnetization is used. There arises a problem that the magnetization recorded on the recording medium is canceled and magnetic information is erased, so-called pole erase. It is considered that such a problem of pole erase occurs because the influence of shape anisotropy increases in the pole portion by narrowing the width of the pole portion.

In order to solve such a problem of pole erasure, the main magnetic pole has a narrowing portion in which the cross-sectional area parallel to the air bearing surface (the surface facing the recording surface of the recording medium) decreases toward the air bearing surface. Has been proposed in which the ratio of the distance from the position closest to the air bearing surface to the main magnetic pole air bearing surface and the area of the main magnetic pole air bearing surface is larger than 0 and smaller than 0.002 [nm ⁻¹ ]. (See Patent Document 1).

Patent Documents 2 to 4 disclose uniaxial magnetic anisotropic thin films or magnetic thin films.
JP 2003-296906 A JP-A-7-86035 Japanese Patent Laid-Open No. 9-82522 Japanese Patent Laid-Open No. 7-86038

  However, it has been found that the magnetic head described in Patent Document 1 cannot sufficiently prevent the occurrence of pole erasure during recording on a recording medium.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a magnetic head for perpendicular magnetic recording that can sufficiently prevent the occurrence of pole erasure during recording on a recording medium. .

（上記式（１）中、Ｈｋは前記材料の異方性磁界（単位はＡ／ｍ）を、σは前記材料の応力（単位はＭＰａ）を、λは前記材料の磁歪定数を表す）で表されるパラメータＰが０．２以上で且つ２０よりも小さい、
ことを特徴とする垂直磁気記録用磁気ヘッドである。 In order to solve the above problems, the present invention has a medium facing surface that is disposed to face a recording surface of a recording medium, and records magnetic information on the recording medium by releasing magnetic flux toward the recording surface of the recording medium. In a magnetic head for perpendicular magnetic recording, a pole portion provided with a magnetic pole that emits magnetic flux toward the recording surface of the recording medium and a return yoke connected to the magnetic pole, the magnetic pole being provided on the recording medium side And a yoke portion provided on the opposite side to the medium facing surface with respect to the pole portion, and the material constituting the magnetic pole has a magnetostriction constant λ of 10 × 10 ⁻⁶ or more and 60 × 10 ⁻⁶ or less. And the following formula:

(In the above formula (1), Hk represents the anisotropic magnetic field (unit: A / m) of the material, σ represents the stress (unit: MPa) of the material, and λ represents the magnetostriction constant of the material). The represented parameter P is 0.2 or more and less than 20;
This is a magnetic head for perpendicular magnetic recording.

  According to this magnetic head for perpendicular magnetic recording, when the magnetic head for perpendicular magnetic recording is mounted on a magnetic recording device and magnetic information is recorded on the recording medium with the medium facing surface facing the recording surface of the recording medium, The occurrence of pole erase can be sufficiently prevented.

  If the parameter P expressed by the above formula is less than 0.2, the influence of the magnetoelastic effect increases, the magnetic domain structure in the yoke portion becomes unstable, and pole erasure is likely to occur. On the other hand, if the parameter P is 20 or more, the magnetic pole cannot be sufficiently saturated with the magnetic field generated from the coil, and the recording ability may be insufficient.

  In the magnetic head for perpendicular magnetic recording, it is preferable that the anisotropic magnetic field Hk of the material is 2000 A / m to 25000 A / m and the stress σ is 100 MPa to 1000 MPa.

  When the anisotropic magnetic field Hk of the material is less than 2000 A / m, the magnetic domain structure tends to become unstable compared with the case where the anisotropic magnetic field Hk is 2000 A / m or more, and the anisotropic magnetic field Hk is 25000 A. If it exceeds / m, the magnetic pole cannot be sufficiently saturated with the magnetic field generated from the coil as compared with the case where the anisotropic magnetic field Hk is 25000 A / m or less, and the recording ability may be insufficient. In addition, when the stress σ is less than 100 MPa, the effect of tensile stress in the pole portion is reduced compared to the case where the stress σ is 100 MPa or more, and pole erasure tends to occur in the pole portion. On the other hand, when the stress σ exceeds 1000 MPa, the pole part may be peeled as compared with the case where the stress σ is 1000 MPa or less.

In the magnetic head for perpendicular magnetic recording, the saturation magnetic flux density at the magnetic pole is preferably 1.5 (Wb / m ² ) or more.

When the saturation magnetic flux density is less than 1.5 (Wb / m ² ), sufficient magnetic flux for saturation recording of the recording medium from the magnetic pole is not released, and the recording ability tends to be insufficient.

  In the magnetic head for perpendicular magnetic recording, the magnetic pole is preferably fixed on a flat surface, and the thickness of the magnetic pole is preferably 0.15 to 0.4 μm.

  When the thickness of the magnetic pole is less than 0.15 μm, the magnetic pole can easily take an island-like magnetic domain structure or a single magnetic domain structure compared to the case where the magnetic pole thickness is 0.15 μm or more, and a stable magnetic domain structure is formed. As a result, it tends to lead to the occurrence of pole erase. On the other hand, when the magnetic pole thickness exceeds 0.4 μm, when magnetic information is recorded with a skew angle with respect to the recording medium, the erase band for the surrounding tracks tends to increase and the track density tends to decrease. Further, if the plate-like magnetic pole is not fixed on the flat surface of the member, the formation of a stable magnetic domain structure may be hindered by the recess or protrusion in the magnetic pole, and an unstable magnetic domain structure may be formed.

  In the magnetic head for perpendicular magnetic recording, the ratio (L / W) of the pole width W defining the track width to the length L along the direction perpendicular to the medium facing surface of the pole portion is 0. It is preferably 5 or more and 3 or less.

  When the ratio is less than 0.5, pole erase does not occur remarkably, and the superiority of the present invention cannot be exhibited. If the ratio exceeds 2, the magnetic flux generated from the magnetic poles may be reduced and the recording ability may be reduced.

  In the magnetic head for perpendicular magnetic recording, the ratio (YL / YW) of the maximum width YW in the yoke portion to the maximum length YL along the direction perpendicular to the medium facing surface of the magnetic pole is 0.33. It is preferable that it is 3 or less.

  When the ratio is less than 0.33, the effect of shape anisotropy in the transverse direction, that is, the direction parallel to the medium facing surface becomes dominant, and the superiority of the present invention that stabilizes the magnetic domain structure cannot be exhibited. On the other hand, when the ratio exceeds 3, the effect of shape anisotropy in the height direction, that is, the direction orthogonal to the medium facing surface becomes dominant, and it tends to be difficult to stabilize the magnetic domain structure.

  In the magnetic head for perpendicular magnetic recording, it is preferable that a 180-degree domain wall is parallel to the medium facing surface in the yoke portion.

  In this case, when the magnetic head for perpendicular magnetic recording is attached to the magnetic recording apparatus and magnetic information is recorded on the recording medium, the occurrence of pole erasure can be more sufficiently prevented.

In the magnetic head for perpendicular magnetic recording, the material constituting the magnetic _{pole, (Fe X Co 1-X} ) 1-Y A Y or _{(Fe X Co 1-X)} 1-Y (A W B 1-W ) Containing _Y ,
X, Y and W are respectively the following formulas:
0.5 ≦ X ≦ 1
0 ≦ Y ≦ 0.1
0 ≦ W ≦ 0.5
Meets

  The element constituting A is selected from the group consisting of B, C, N, Al, Si, Ni, Cu, Zr, Hf and Ta;

The element constituting B is selected from the group consisting of O, N, and C.
It is preferable.

  In this case, there is an advantage that the saturation magnetic flux density can be further increased and a sufficient recording ability can be secured as compared with the case where the material does not have the above configuration.

Of the materials constituting the magnetic poles, (Fe _0.7 Co _0.3 ) _0.95 B _0.05 , (Fe _0.7 Co _0.3 ) _0.95 (Zr _0.33 O _0.67 ) Any one of _0.05 , (Fe _0.7 Co _0.3 ) _0.96 (Zr _0.33 O _0.67 ) _0.04 and Fe _0.6 Co _0.36 Ni _0.04 is particularly preferable. When the above material is used as a material constituting the magnetic pole, the occurrence of pole erase can be surely prevented.

  According to the magnetic head for perpendicular magnetic recording of the present invention, it is possible to sufficiently prevent the occurrence of pole erasure during recording on a recording medium.

(First embodiment)
FIG. 1 is a sectional view showing an embodiment of a magnetic head for perpendicular magnetic recording according to the present invention.

  As shown in FIG. 1, the magnetic head 2 for perpendicular magnetic recording is arranged to face the recording medium 3. The recording medium 3 includes a recording layer 5 having a recording surface 3a and a soft magnetic backing layer 7 laminated on the recording layer 5. The magnetic head 2 for perpendicular magnetic recording is specifically described as follows. The recording medium 3 is arranged on the recording surface 3a side.

The magnetic head 2 for perpendicular magnetic recording has a substrate 4 made of, for example, Al ₂ O ₃ .TiC, and is a medium facing surface that is orthogonal to the one surface 4 a of the substrate 4 and is opposed to the recording surface 3 a of the recording medium 3. S. Then, the magnetic head 2 reads the signals in the insulating layer 6 made of alumina, for example, and the recording layer 5 of the recording medium 3 on the one surface 4a of the substrate 4 on the medium facing surface S side and records the signals in the recording layer 5. A reproducing head unit 18 for reproducing information, an insulating layer 14 made of alumina, for example, a recording head unit 20 for emitting magnetic flux toward the recording surface 3a of the recording medium 3 and recording magnetic information on the recording layer 5, An insulating layer 30 made of alumina is laminated in this order.

  The reproducing head unit 18 is configured by laminating a read shield layer 8, an insulating layer 10 made of alumina, for example, and a read shield layer 12 in this order on the insulating layer 6. In the insulating layer 10, an MR element 19 is provided on the medium facing surface S side so as to be exposed to the recording surface 3 a of the recording medium 3. The MR element 19 is an element that generates a current by detecting a change in the magnetic field in the recording layer 5 with high sensitivity when the magnetic head 2 is moved relative to the recording surface 3a. As such an MR element 19, for example, a GMR element utilizing a giant magnetoresistance effect or a TMR element utilizing a tunnel magnetoresistance effect is used.

  The recording head unit 20 includes a magnetic pole layer 21, a yoke layer 17 provided on the insulating layer 14 side of the magnetic pole layer 21, an insulating layer 24 provided on the opposite side of the magnetic pole layer 21 from the yoke layer 17, and an insulating layer 24. A coil 22 provided above, an insulating layer 26 provided on the insulating layer 24 so as to cover the coil 22, and a return yoke 16 provided on the insulating layer 26 are provided.

  Here, the coil 22 has a winding structure wound around one end portion 16 a of the return yoke 16, and the return yoke 16 is provided on the insulating layer 26 so as to sandwich the coil 22 together with the pole layer 21. It has been. The other end portion 16b of the return yoke 16 is exposed to the recording surface 3a of the recording medium 3 on the medium facing surface S side, and the one end portion 16a penetrates the insulating layer 24 directly to the pole layer 21. It is connected. Further, one end of the pole layer 21 is exposed to the recording surface 3 a of the recording medium 3 on the medium facing surface S side. Accordingly, when a current is passed through the coil 22, a magnetic flux is emitted from the pole layer 21 toward the recording surface 3 a of the recording medium 3. This magnetic flux passes through the recording layer 5, the backing layer 7 and the recording layer 5 of the recording medium 3, enters the return yoke 16, and returns to the pole layer 21.

  The yoke layer 17 and the insulating layer 14 are connected to form a flat surface F, and the pole layer 21 is fixed on the flat surface F from the yoke layer 17 to the insulating layer 14.

  FIG. 2 is a front view showing the pole layer 21 of FIG. As shown in FIG. 2, the pole layer 21 includes a pole portion 21a provided on the medium facing surface S side in the magnetic head 2 and extending in a direction perpendicular to the medium facing surface S, and the medium facing surface with respect to the pole portion 21a. S and a yoke portion 21b provided on the opposite side. Here, the yoke layer 21 is laminated with the yoke layer 17, and one end portion 16 a of the return yoke 16 is connected to the yoke portion 21 b. Further, the yoke portion 21b is configured to gradually increase in width as it moves away from the medium facing surface S with respect to the pole portion 21a, and to maintain a constant value after reaching a certain width.

（上記式（１）中、Ｈｋは上記軟磁性材料の異方性磁界（単位はＡ／ｍ）を、σは上記軟磁性材料の応力（単位はＭＰａ）を、λは上記軟磁性材料の磁歪定数を表す）
で表されるパラメータＰが０．２以上で且つ２０よりも小さくなっている。 Here, the pole layer 21 has magnetic uniaxial anisotropy in a plane orthogonal to the thickness direction, and the soft magnetic material constituting the pole layer 21 is 10 × 10 ⁻⁶ or more and 60 ×. It has a magnetostriction constant λ of 10 ⁻⁶ or less, and the following formula:

(In the above formula (1), Hk is the anisotropic magnetic field (unit: A / m) of the soft magnetic material, σ is the stress (unit: MPa) of the soft magnetic material, and λ is the soft magnetic material. Represents magnetostriction constant)
The parameter P represented by is 0.2 or more and smaller than 20.

The soft magnetic material constituting the magnetic pole layer 21 is not particularly limited as long as the parameter P is 0.2 or more and smaller than 20, and such a soft magnetic material is preferably (Fe _{X Co 1-X) 1-Y} a Y or _{(Fe X Co 1-X)} 1-Y (a W B 1-W) which is configured to include a _Y is used. In the present embodiment, in the pole layer 21, the pole portion 21a and the yoke portion 21b are made of the same material.

Here, X, Y and W are respectively the following formulas:
0.5 ≦ X ≦ 1
0 ≦ Y ≦ 0.1
0 ≦ W ≦ 0.5
It satisfies.

  The element constituting A is selected from the group consisting of B, C, N, Al, Si, Ni, Cu, Zr, Hf, and Ta, and the element constituting B is composed of O, N, and C. Selected from the group.

Specifically, as the soft magnetic material, (Fe _0.7 Co _0.3 ) _0.95 B _0.05 , (Fe _0.7 Co _0.3 ) _0.95 (Zr _0.33 O _{0 .67} ) _0.05 , (Fe _0.7 Co _0.3 ) _0.96 (Zr _0.33 O _0.67 ) _0.04 , Fe _0.6 Co _0.36 Ni _0.04, etc. are used. .

  However, the element constituting A and the element constituting B may be elements other than those described above as long as the parameter P is 0.2 or more and less than 20. Even in this case, when magnetic information is recorded on the recording layer 5 of the recording medium 3 using the magnetic head 2, it is possible to sufficiently prevent the occurrence of pole erase.

  Next, the operation of the above-described magnetic head 2 for perpendicular magnetic recording will be described.

  The perpendicular magnetic recording magnetic head 2 is disposed to face the recording medium 3. Specifically, the magnetic head 2 for perpendicular magnetic recording is arranged such that the medium facing surface S faces the recording surface 3 a of the recording medium 3. When recording magnetic information on the recording medium 3, a current is passed through the coil 22. Then, a magnetic flux is generated around the coil 22, and the magnetic flux is emitted from the pole portion 21 a of the pole layer 21 toward the recording surface 3 a of the recording medium 3. This magnetic flux passes through the recording layer 5, the backing layer 7 and the recording layer 5 of the recording medium 3, enters the return yoke 16, and returns to the pole layer 21. At this time, magnetization is formed in the recording layer 5 of the recording medium 3 in a direction perpendicular to the recording surface 3a. Here, when the recording medium 3 rotates, magnetization is successively formed in the recording layer 5 of the recording medium 3. Thus, magnetic information is recorded on the recording layer 5 of the recording medium 3.

  At this time, since the pole layer 21 is configured as described above, it is possible to sufficiently prevent the magnetization once formed in the recording layer 5 as described above from being canceled, that is, the occurrence of pole erase. The Therefore, according to the magnetic head 2, the disappearance of magnetic information can be sufficiently prevented, and the reliability of the magnetic disk device on which the magnetic head 2 is mounted can be improved.

  In the magnetic head 2 for perpendicular magnetic recording, the pole layer 21 has a layer shape and is fixed on the flat surface F formed by the insulating layer 14 and the yoke layer 17. For this reason, in the magnetic pole layer 21, formation of a stable magnetic domain structure by a recess or a protrusion is hindered, and an unstable magnetic domain structure is sufficiently prevented from being formed. Therefore, the occurrence of pole erasure at the time of magnetic information recording is more sufficiently prevented as compared with the case where it is fixed on a non-flat surface.

  In the magnetic pole layer 21, it is preferable that the anisotropic magnetic field Hk is 2000 A / m or more and 25000 A / m or less, and the stress σ is 100 MPa or more and 1000 MPa or less.

  When the anisotropic magnetic field Hk is less than 2000 A / m, the magnetic domain structure tends to become unstable compared to the case where the anisotropic magnetic field Hk is 2000 A / m or more, and the anisotropic magnetic field Hk is 25000 A / m. If it exceeds, the magnetic pole cannot be sufficiently saturated with the magnetic field generated from the coil as compared with the case where the anisotropic magnetic field Hk is 25000 A / m or less, and the recording ability may be insufficient. Further, when the stress σ is less than 100 MPa, the effect of the tensile stress in the pole portion 21a is reduced and pole erasure tends to occur in the pole portion 21a as compared with the case where the stress σ is 100 MPa or more. On the other hand, when the stress σ exceeds 1000 MPa, the pole portion 21a may be peeled as compared to the case where the stress σ is 1000 MPa or less.

Further, the saturation magnetic flux density of the soft magnetic material constituting the magnetic pole layer 21 is preferably 1.5 (Wb / m ² ) or more, and more preferably 1.8 (Wb / m ² ) or more. When the saturation magnetic flux density of the soft magnetic material constituting the magnetic pole layer 21 is less than 1.5 (Wb / m ² ), sufficient magnetic flux for saturation recording of the recording medium 3 from the magnetic pole layer 21 is not released, The recording ability tends to be insufficient.

  The thickness of the pole layer 21 is preferably 0.15 to 0.4 μm. When the thickness of the pole layer 21 is less than 0.15 μm, compared to the case where the thickness of the pole layer 21 is 0.15 μm or more, an island-like magnetic domain or a single domain structure is easily formed in the pole layer 21. As a result, it becomes difficult to form a stable magnetic domain structure, and as a result, pole erasure tends to occur. On the other hand, when the thickness of the pole layer 21 exceeds 0.4 μm, an erase band with respect to surrounding tracks increases when magnetic information is recorded with a skew angle with respect to the recording medium 3, and the track density in the recording medium 3 is increased. Tends to decrease.

  If the ratio is less than 0.5, pole erasure does not occur remarkably and the superiority of the magnetic head 2 cannot be exhibited. If the ratio exceeds 2, there is a possibility that the magnetic flux generated from the pole layer 21 is reduced and the recording ability is lowered.

  The ratio (YL / YW) between the maximum width YW of the yoke portion 21b and the maximum length YL along the direction perpendicular to the medium facing surface S of the pole layer 21 is 0.33 or more and 3 or less. preferable.

  If the ratio is less than 0.33, the effect of shape anisotropy in the transverse direction, that is, the direction parallel to the medium facing surface S is dominant, and the superiority of the magnetic head 2 that stabilizes the magnetic domain structure cannot be exhibited. . On the other hand, if the ratio exceeds 3, the effect of shape anisotropy in the height direction, that is, the direction orthogonal to the medium facing surface S becomes dominant, and it tends to be difficult to stabilize the magnetic domain structure.

  Further, in the yoke portion 21b in the pole layer 21, it is preferable that the 180-degree domain wall 50 is parallel to the medium facing surface S as shown in FIG. In this case, when the magnetic head 2 for perpendicular magnetic recording is mounted on the magnetic recording apparatus and magnetic information is recorded on the recording medium 3, the occurrence of pole erasure can be prevented more sufficiently.

(Second Embodiment)
Next, a second embodiment of the magnetic head for perpendicular magnetic recording according to the present invention will be described. In the description of the present embodiment, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 4 is a sectional view showing a second embodiment of the magnetic head for perpendicular magnetic recording of the present invention. As shown in FIG. 4, the perpendicular magnetic recording magnetic head 102 of this embodiment is different from the perpendicular magnetic recording magnetic head 20 of the first embodiment in that the recording head unit 120 has the following configuration. To do.

  That is, the recording head unit 120 includes the return yoke 16 provided adjacent to the read shield layer 12 on the medium facing surface S side. An insulating layer 24 is formed on the return yoke 16, and a coil 22 is provided on the insulating layer 24. The coil 22 is covered with an insulating layer 26. A yoke layer 17 is provided on the insulating layer 26. Further, an insulating layer 28 that is adjacent to the yoke layer 17 and forms a flat surface F together with the yoke layer 17 is provided on the insulating layer 26. The insulating layer 28 is made of alumina, for example. On the flat surface F, the pole layer 21 is provided. The pole layer 21 covers the entire flat surface of the yoke layer 17 in the flat surface F.

  Here, the coil 22 has a winding structure wound around one end portion 17 a of the yoke layer 17, and the yoke layer 17 is provided on the insulating layer 26 so as to sandwich the coil 22 together with the return yoke 16. It has been. The other end 16 b of the return yoke 16 is exposed to the recording surface 3 a of the recording medium 3 on the medium facing surface S side, and the one end 16 a of the return yoke 16 is directly connected to the yoke layer 17. Yes. Further, one end of the pole layer 21, that is, the pole portion 21 a is exposed to the recording surface 3 a of the recording medium 3 on the medium facing surface S side.

  Accordingly, when a current is passed through the coil 22, a magnetic flux is emitted from the pole layer 21 toward the recording surface 3 a of the recording medium 3. This magnetic flux passes through the recording layer 5, the backing layer 7 and the recording layer 5 of the recording medium 3, enters the return yoke 16, and then returns to the pole layer 21 through the yoke layer 17.

  Also in the magnetic head 102 of the present embodiment, when magnetic information is recorded on the recording layer 5 of the recording medium 3 using the magnetic head 102, the magnetization once formed in the recording layer 5 is canceled, that is, pole erasure occurs. Occurrence is sufficiently prevented. Therefore, according to the magnetic head 102, the disappearance of magnetic information can be sufficiently prevented, and the reliability of the magnetic disk device on which the magnetic head 102 is mounted can be improved.

(Third embodiment)
FIG. 5 is a sectional view showing a third embodiment of the magnetic head for perpendicular magnetic recording of the present invention.

  As shown in FIG. 5, the perpendicular magnetic recording magnetic head 202 of this embodiment differs from the perpendicular magnetic recording magnetic head 2 of the first embodiment in that the recording head unit 220 is configured as follows. To do.

  That is, the recording head unit 220 includes the return yoke 16 provided on the medium facing surface S side with respect to the read shield layer 12 via the insulating layer 14. An insulating layer 24 is formed on the return yoke 16, and a coil 22 is provided on the insulating layer 24. The coil 22 is covered with an insulating layer 26. A yoke layer 17 is provided on the insulating layer 26. Further, an insulating layer 28 that is adjacent to the yoke layer 17 and forms a flat surface F together with the yoke layer 17 is provided on the insulating layer 26. On the flat surface F, the pole layer 21 is provided.

  Here, the coil 22 has a winding structure wound around one end portion 17 a of the yoke layer 17, and the yoke layer 17 is provided on the insulating layer 26 so as to sandwich the coil 22 together with the return yoke 16. It has been. The other end 16 b of the return yoke 16 is exposed to the recording surface 3 a of the recording medium 3 on the medium facing surface S side, and the one end 16 a of the return yoke 16 is directly connected to the yoke layer 17. Yes. Further, one end of the pole layer 21, that is, the pole portion 21 a is exposed to the recording surface 3 a of the recording medium 3 on the medium facing surface S side. The pole layer 21 covers a part of the flat surface F of the flat surface F (the end on the medium facing surface S side) of the flat surface of the yoke layer 17.

  Accordingly, when a current is passed through the coil 22, a magnetic flux is emitted from the pole layer 21 toward the recording surface 3 a of the recording medium 3. This magnetic flux passes through the recording layer 5, the backing layer 7 and the recording layer 5 of the recording medium 3, enters the return yoke 16, and then returns to the pole layer 21 through the yoke layer 17.

  Also in the magnetic head 202 of the present embodiment, when magnetic information is recorded on the recording layer 5 of the recording medium 3 using the magnetic head 202, the magnetization once formed in the recording layer 5 is canceled, that is, pole erasure occurs. Occurrence is sufficiently prevented. Therefore, according to the magnetic head 202, the disappearance of magnetic information can be sufficiently prevented, and the reliability of the magnetic disk device on which the magnetic head 202 is mounted can be improved.

  The present invention is not limited to the first to third embodiments described above. For example, in the first to third embodiments, the entire pole layer 21 is made of the same material. However, in the magnetic head of the present invention, the parameter P is shown in each embodiment in the yoke portion 21b and the pole portion 21a. As long as it is within the specified range, it may be made of different materials.

  Next, the content of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

(Examples 1-4 and Comparative Examples 1-4)
A magnetic head 2 for perpendicular magnetic recording was produced as follows.

That is, first, an insulating layer 6 made of alumina is formed on one surface 4a of an AlTiC substrate (Al ₂ O ₃ .TiC) 4, and a read shield layer 8 made of NiFe and an insulating layer made of alumina are formed on the insulating layer 6. 10 and a read shield layer 12 made of NiFe were laminated in this order to form a reproducing head portion 18. In the process of forming the insulating layer 10, the MR element 19 was formed so that the end face was exposed on the medium facing surface S side. A GMR element was used as the MR element 19.

  Next, an insulating layer 14 made of alumina was formed on the reproducing head portion 18, and a yoke layer 17 made of permalloy was formed in the insulating layer 14 so that a flat surface F was formed. A magnetic pole layer 21 was formed on the flat surface F, an insulating layer 24 made of alumina was formed on the magnetic pole layer 21, and an opening was formed in the insulating layer 24.

  Next, after forming the coil 22 on the insulating layer 24, an insulating layer 26 made of resist was formed on the coil 22.

  Subsequently, the return yoke layer 16 made of NiFe was formed on the insulating layer 26. At this time, one end 16 a of the return yoke layer 16 was directly connected to the pole layer 21 through the opening of the insulating layer 24. Then, an insulating layer 30 made of alumina was formed on the return yoke layer 16, and thus the perpendicular recording magnetic head 2 was obtained.

  At this time, the thickness of the pole layer 21 was 0.25 μm, and the pole portion 21a and the yoke portion 21b were used. The width W of the pole portion 21a was 0.12 μm, the length L of the pole portion 21a was 0.18 μm, and the ratio (L / W) of the width and length of the pole portion 21a was 1.5.

  The pole layer 21 according to Example 4 and Comparative Examples 1 and 4 was formed by electrodeposition plating using the bath composition and bath conditions shown in Table 1 below.

The pole layers 21 according to Examples 1 to 3 and Comparative Examples 2 and 3 were formed by DC magnetron sputtering under the conditions shown in Table 2 below. The sputtering method was performed while applying a magnetic field in the transverse direction.

With respect to the magnetic head 2 obtained as described above, the saturation magnetic flux density Bs, the anisotropic magnetic field Hk, the magnetostriction constant λ, the film stress σ, and the parameter P were measured. The results are shown in Table 3.

  Bs, Hk, λ, σ and parameter P in Table 3 were measured as follows.

(1) Saturation magnetic flux density; Bs
Bs was measured using a VSM (Vibrating sample magnetometer). However, since measurement was not possible in the state of the magnetic head 2, a measurement sample according to the bath composition and bath conditions shown in Table 1 was prepared, and Bs was obtained from this measurement sample.

(2) Anisotropic magnetic field; Hk
Hk was obtained from a magnetic hysteresis loop in the hard axis direction using a BH loop tracer.

(3) Magnetostriction constant; λ
The magnetostriction constant λ was obtained from the amount of displacement of the thin film when a magnetic field was applied using an optical lever method.

(4) Stress; σ
The stress σ was calculated by substituting each parameter into the following formula.
^{_{σ = E · h s 2/}} 6 (1-VS) rh f
E: Young's modulus, h _s : substrate thickness, VS: Poisson's ratio,
r: radius of curvature, h _f : film thickness

  When the magnetic pole layer 21 was formed by sputtering, the magnetic pole layer was formed on a glass substrate, the warpage before and after film formation on the glass substrate was measured, and the stress was calculated. The size of the substrate used was 10 mm × 20 mm × 0.2 mm (thickness). The Young's modulus E was 617 GPa, and the Poisson's ratio VS was 0.21.

  When the magnetic pole layer 21 is formed by electrodeposition plating, the magnetic pole layer 21 is formed on the AlTiC substrate, the warpage before and after the film formation on the AlTiC substrate is measured from optical interference, and the stress is measured. Calculated. The size of the substrate used was a 6-inch AlTiC substrate (thickness 2 mm). The Young's modulus E was 407 GPa, and the Poisson's ratio VS was 0.24.

(5) Evaluation of magnetic head for perpendicular magnetic recording The magnetic head for perpendicular magnetic recording obtained as described above was evaluated as follows. That is, a 130 kFCI test signal is recorded on one track of 70 sectors of a perpendicular magnetic recording medium having a coercive force of 4700 Oe, an initial output is measured, and a 50 kFCI pole erase test signal is recorded at the head of each sector. did. Then, after 300 pole erase tests were repeated, the residual output of the test signal was calculated as the intensity residual output signal intensity (%). The results are shown in Table 3 and FIG.

  Here, it was defined that pole erasure occurred when the residual output signal intensity was 90% or less. If pole erasure does not occur, the magnetic head is evaluated as good and “○” is entered in Table 3. If pole erasure occurs, the magnetic head is evaluated as not good. “X” was entered in 3.

  As is apparent from the results of Table 3 and FIG. 6, according to the magnetic heads of Examples 1 to 4, it was found that the residual output signal intensity exceeded 90% and no pole erase occurred. On the other hand, according to the magnetic heads of Comparative Examples 1 to 4, it was found that the residual output signal intensity was 90% or less, and pole erase occurred.

From this, the material constituting the magnetic pole has a magnetostriction constant λ of 10 × 10 ⁻⁶ or more and 60 × 10 ⁻⁶ or less, and the parameter P represented by the above formula (1) is 0.2 or more and 20 It was confirmed that the pole erase could be sufficiently prevented by a smaller magnetic head.

1 is a cross-sectional view showing an embodiment of a magnetic head for perpendicular magnetic recording according to the present invention. It is a front view which shows the magnetic pole of FIG. It is a figure which shows the magnetic domain structure in the magnetic pole of FIG. It is sectional drawing which shows other embodiment of the magnetic head for perpendicular magnetic recording of this invention. It is sectional drawing which shows other embodiment of the magnetic head for perpendicular magnetic recording of this invention. 6 is a graph showing a relationship between a residual output signal intensity and a parameter P in the magnetic heads for perpendicular magnetic recording according to Examples 1 to 4 and Comparative Examples 1 to 4.

Explanation of symbols

2, 102, 202 ... Magnetic head for perpendicular magnetic recording 3 ... Recording medium 3a ... Recording surface 16 ... Return yoke layer (return yoke),
17 ... Yoke layer 21 ... Pole layer (magnetic pole)
21a ... pole part 21b ... yoke part S ... medium facing surface F ... flat surface W ... pole part width L ... pole part length YW ... maximum width in yoke part YL ... in a direction perpendicular to the medium facing surface in the magnetic pole Maximum length along

Claims (9)

In a magnetic head for perpendicular magnetic recording, which has a medium facing surface disposed opposite to a recording surface of a recording medium and emits magnetic flux toward the recording surface of the recording medium to record magnetic information on the recording medium.
A magnetic pole that emits a magnetic flux toward the recording surface of the recording medium, and a return yoke coupled to the magnetic pole,
The magnetic pole has a pole portion provided on the recording medium side, and a yoke portion provided on the opposite side to the medium facing surface with respect to the pole portion,
The material constituting the magnetic pole has a magnetostriction constant λ of 10 × 10 ⁻⁶ or more and 60 × 10 ⁻⁶ or less, and the following formula:

(In the above formula (1), Hk represents the anisotropic magnetic field (unit: A / m) of the material, σ represents the stress (unit: MPa) of the material, and λ represents the magnetostriction constant of the material). The represented parameter P is 0.2 or more and less than 20;
A magnetic head for perpendicular magnetic recording.   2. The magnetic head for perpendicular magnetic recording according to claim 1, wherein the material has an anisotropic magnetic field Hk of 2000 A / m to 25000 A / m and a stress σ of 100 MPa to 1000 MPa. The magnetic head for perpendicular magnetic recording according to claim 1, wherein a saturation magnetic flux density at the magnetic pole is 1.5 (Wb / m ² ) or more.   The magnetic head for perpendicular magnetic recording according to claim 1, wherein the magnetic pole is fixed on a flat surface, and the thickness of the magnetic pole is 0.15 to 0.4 μm.   2. The ratio (L / W) between the width W of the pole portion that defines the track width and the length L along the direction perpendicular to the medium facing surface of the pole portion is 0.5 or more and 3 or less. The magnetic head for perpendicular magnetic recording as described in any one of -4.   The ratio (YL / YW) between the maximum width YW of the yoke portion and the maximum length YL of the magnetic pole along the direction perpendicular to the medium facing surface is 0.33 or more and 3 or less. A magnetic head for perpendicular magnetic recording according to any one of the above.   The magnetic head for perpendicular magnetic recording according to any one of claims 1 to 6, wherein a 180-degree domain wall is parallel to the medium facing surface in the yoke portion. Material constituting the magnetic pole _is configured to include a _{(Fe X Co 1-X)} 1-Y A Y or _{(Fe X Co 1-X)} 1-Y (A W B 1-W) Y,
X, Y and W are respectively the following formulas:
0.5 ≦ X ≦ 1
0 ≦ Y ≦ 0.1
0 ≦ W ≦ 0.5
Meets
The element constituting A is selected from the group consisting of B, C, N, Al, Si, Ni, Cu, Zr, Hf and Ta;
The element constituting B is selected from the group consisting of O, N, and C.
The magnetic head for perpendicular magnetic recording according to claim 1. The materials constituting the magnetic pole are (Fe _0.7 Co _0.3 ) _0.95 B _0.05 , (Fe _0.7 Co _0.3 ) _0.95 (Zr _0.33 O _0.67 ) _{0 .05} , (Fe _0.7 Co _0.3 ) _0.96 (Zr _0.33 O _0.67 ) _0.04 and Fe _0.6 Co _0.36 Ni _0.04 2. A magnetic head for perpendicular magnetic recording described in 1.

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