JP2008108352A - Perpendicular magnetic recording head device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a perpendicular magnetic recording head highly reliable in pressure-reduced environment by suppressing a PTP phenomenon. <P>SOLUTION: This device has a magnetic layer 24 having a main pole exposed on a surface facing a recording medium M, a return yoke layer 27 formed on the magnetic layer 24 via a nonmagnetic layer, coil layers 18 and 23 for applying recording magnetic fields to the magnetic layer 24 and the return yoke layer 27, and a pair of shield layers 13 and 16 between which an insulating layer 15 having a reading element 14 exposed on the surface facing the recording medium M is held. The return yoke layer 27 has an opening 27d extended from a position where the width of a main magnetic pole in a track width direction is narrowed to a height direction depth side in a plane view. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a perpendicular magnetic recording head device that performs recording by applying a magnetic field in a direction perpendicular to the medium surface of a recording medium.

The perpendicular magnetic recording head device has a laminated structure in which a return yoke layer is provided on a surface facing a recording medium (medium facing surface) via a nonmagnetic insulating layer on the main magnetic pole layer. The main magnetic pole layer and the return yoke layer are magnetically connected at the depth in the height direction from the medium facing surface. A coil layer for applying a recording magnetic field to the main magnetic pole layer and the return yoke layer is embedded in the nonmagnetic insulating layer. In the magnetic head device having such a configuration, when a coil layer is energized, a recording magnetic field is induced between the main magnetic pole layer and the return yoke layer, and this recording magnetic field is recorded from the medium facing surface of the main magnetic pole layer to the recording medium. Perpendicularly enters the hard film of the recording medium, returns to the return yoke layer through the soft film of the recording medium. As a result, information is recorded in a region facing the main magnetic pole layer in the recording medium (Patent Document 1).
JP 2005-122831 A

  In the perpendicular magnetic recording head device, when the internal temperature becomes high during information recording, the difference in thermal expansion coefficient between the material constituting the magnetic layer such as the shield layer and the insulating material around the magnetic layer As a result, a so-called PTP (Pole Tip Protrusion) phenomenon occurs in which the magnetic layer easily protrudes from the medium facing surface. In this case, if the PTP phenomenon occurs and the protrusion of the magnetic layer increases, there is a problem in that the reliability between the medium and the head is reduced when the head flying height is reduced in a reduced pressure environment and the reliability is lowered. .

  The present invention has been made in view of this point, and an object thereof is to provide a perpendicular magnetic recording head device that suppresses the PTP phenomenon and has high reliability in a reduced pressure environment.

  The perpendicular magnetic recording head device of the present invention is provided with a first magnetic layer having a main magnetic pole exposed at a surface facing a recording medium, a nonmagnetic layer with respect to the magnetic layer, and the main magnetic pole A second magnetic layer having a wide width; and a coil layer for applying a recording magnetic field to the first magnetic layer. The second magnetic layer overlaps with the main magnetic pole in a plan view and is formed on the medium facing surface. The exposed surface extends in the track width direction and has an opening extending in the depth direction.

  According to this configuration, since the volume of the return yoke layer is relatively small, it is possible to reduce the influence of the difference in thermal expansion coefficient between the constituent material of the return yoke layer and the constituent materials of the surrounding layers. As a result, the PTP phenomenon can be suppressed.

  In the perpendicular magnetic recording head device of the present invention, it is preferable that the opening extends from the position where the width of the main magnetic pole in the track width direction is narrowed to the back side in the height direction.

  In the perpendicular magnetic recording head device of the present invention, when the second magnetic layer is a return yoke layer, the opening is formed to a position that does not reach the connecting portion that is located on the far side in the height direction from the facing surface. It is preferable that

  The perpendicular magnetic recording head device of the present invention is provided with a first magnetic layer having a main magnetic pole exposed at a surface facing a recording medium, a nonmagnetic layer with respect to the magnetic layer, and the main magnetic pole A second magnetic layer having a wide width; and a coil layer for applying a recording magnetic field to the first magnetic layer. The second magnetic layer overlaps with the main magnetic pole in a plan view and is formed on the medium facing surface. Since the exposed surface extends in the track width direction and has an opening extending in the depth direction, it is possible to suppress the PTP phenomenon and provide a highly reliable perpendicular magnetic recording head device in a reduced pressure environment. it can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view showing a magnetic head provided with a perpendicular magnetic recording head according to an embodiment of the present invention. FIG. 2 is a partial plan view of the perpendicular magnetic recording head shown in FIG. 1 and a partial front view of the return yoke layer. In FIG. 1, X indicates the track width direction, Y indicates the height direction, and Z indicates the film thickness direction. Each direction is orthogonal to the remaining two directions. In the present embodiment, the case where the magnetic layer having the opening is a return yoke layer will be described.

The perpendicular magnetic recording head H _W shown in FIG. 1, it applies a perpendicular magnetic field to a recording medium M, to magnetize a hard film Ma of the recording medium M in the vertical direction. The recording medium M has, for example, a disk shape, has a hard film Ma with high residual magnetization on its surface, and has a soft film Mb with high magnetic permeability inside, and the center of the disk is the center of rotation. Are configured to rotate.

The slider 10 is made of a nonmagnetic material such as Al ₂ O ₃ .TiC. The facing surface 10a of the slider 10 faces the recording medium M. When the recording medium M rotates, the slider 10 floats from the surface of the recording medium M due to the air flow on the surface, or the slider 10 slides on the recording medium M. To do. A nonmagnetic insulating layer 12 made of an inorganic material such as Al ₂ O ₃ or SiO ₂ is formed on the trailing side end surface (upper surface) 10 b of the slider 10, and a reading unit is formed on the nonmagnetic insulating layer 12. H _R is formed.

Reading portion H _R includes a lower shield layer 13 formed on the nonmagnetic insulating layer 12, and an upper shield layer 16 formed over the inorganic insulating layer (gap insulating layer) 15 on the lower shield layer 13 . These shield layers 13 and 16 are formed wider than the main magnetic pole. A reading element 14 is provided in the inorganic insulating layer 15. As the reading element 14, a magnetoresistive effect element such as an AMR (Anisotropic MagnetoResistance) element, a GMR (Giant MagnetoResistance) element, or a TMR (Tunnel MagnetoResistance) element is used.

  A plurality of lower coil pieces 18 made of a conductive material are formed on the upper shield layer 16 with a coil insulating base layer 17 interposed therebetween. The lower coil piece 18 is made of at least one metal material selected from, for example, Au, Ag, Pt, Cu, Cr, Al, Ti, NiP, Mo, Pd, Rh, and Ni. The lower coil piece 18 may be formed by laminating layers made of these nonmagnetic metal materials.

A coil insulating layer 19 made of an inorganic insulating material such as Al ₂ O ₃ or an organic insulating material such as a resist is formed around the lower coil piece 18. The upper surface of the coil insulating layer 19 is formed flat, a plating underlayer (not shown) is formed on this upper surface, and the main magnetic pole layer 24 is provided on this plating underlayer. The periphery of the main magnetic pole layer 24 is filled with an insulating layer 32 made of Al ₂ O ₃ , SiO ₂ or the like, and is flattened so that the upper surface of the main magnetic pole layer 24 and the upper surface of the insulating layer 32 are substantially in the same plane. Has been processed. The main magnetic pole layer 24 is made of a ferromagnetic material having a high saturation magnetic flux density such as NiFe, CoFe, or NiFeCo, and is formed by plating, for example.

  As shown in FIG. 2, the main magnetic pole layer 24 extends from the facing surface H1a to the recording medium (the facing surface H1a is formed in substantially the same plane as the facing surface 10a of the slider 10) in the height direction (Y direction in the drawing). An elongated front part 24a formed with a track width Tw, and a rear part 24b (maximum width dimension T2) having a wider width dimension in the track width direction (X direction in the drawing) than the front part 24a behind the front part 24a in the height direction. And have.

As shown in FIG. 1, a gap layer 21, which is a nonmagnetic layer made of an inorganic material such as Al ₂ O ₃ or SiO ₂ , is formed on the main magnetic pole layer 24. An upper coil piece 23 is formed on the gap layer 21 with a coil insulating base layer 22 interposed therebetween. Since the gap layer 21 also functions as an insulating base of the upper coil piece 23, the coil insulating base layer 22 may not be formed. Similar to the lower layer coil piece 18, a plurality of upper layer coil pieces 23 are formed of a conductive material. The upper layer coil piece 23 is made of, for example, at least one metal material selected from Au, Ag, Pt, Cu, Cr, Al, Ti, NiP, Mo, Pd, Rh, and Ni. Further, the upper coil piece 23 may be formed by stacking layers made of these nonmagnetic metal materials.

  As shown in FIG. 2, the lower layer coil piece 18 and the upper layer coil piece 23 are arranged in a solenoid shape, and the ends of each coil piece in the track width direction (X direction in the drawing) are electrically connected to each other. The lower layer coil piece 18 and the upper layer coil piece 23 are formed with lead portions 18a and 23a, respectively, and current is supplied from the lead portions 18a and 23a to the solenoid coil.

A coil insulating layer 26 made of an inorganic insulating material such as Al ₂ O ₃ or an organic insulating material such as a resist is formed on the upper layer coil piece 23. In the present embodiment, a gap adjusting insulating layer 28 made of an inorganic material or an organic material is formed on the gap layer 21. The front edge of the coil insulating layer 26 overlaps the interval adjusting insulating layer 28. As shown in FIG. 2, the front edge 28a of the gap adjusting insulating layer 28 extends linearly in a direction substantially parallel to the track width direction (X direction in the drawing). The front edge 28a of the gap adjusting insulating layer 28 is formed away from the facing surface H1a by a predetermined distance (gap depth) L1 in the height direction. As shown in FIG. 2, the gap adjusting insulating layer 28 extends long in the track width direction (X direction in the drawing). The width dimension T3 of the front edge 28a of the gap adjusting insulating layer 28 is formed to be at least smaller than the maximum width dimension T2 of the main magnetic pole layer 24.

  When the solenoid coil layer is used, the width dimension of the upper coil piece 23 in the track width direction is always larger than the maximum width dimension T2 of the main magnetic pole layer 24. Therefore, the coil insulating layer 26 that covers the upper coil piece 23 is used. The maximum width dimension T4 is necessarily larger than the maximum width dimension T2 of the main magnetic pole layer 24. The gap adjusting insulating layer 28 is made of, for example, an organic insulating material and is formed by thermosetting. The vertical cross-sectional shape of the spacing adjustment insulating layer 28 is changed from a rectangular shape to a substantially semi-elliptical shape (or at least the upper surface is curved) by the heat treatment. The coil insulating layer 26 partially overlapped on the gap adjusting insulating layer 28 and formed in the height direction is also made of an organic insulating material and is formed by thermosetting. Is formed so as to rise from the upper surface of the gap adjusting insulating layer 28 into a curved shape. The spacing adjusting insulating layer 28 and the coil insulating layer 26 (hereinafter, these two layers may be referred to as “insulating layer 30”) are located above the reference plane when the upper surface of the gap layer 21 is the reference plane (Z in the figure). Direction). The upper surface of the gap layer 21 is exposed around the insulating layer 30. Hereinafter, a region between the front edge 28a of the spacing adjustment insulating layer 28 and the facing surface H1a is referred to as a front region A, and regions on both sides in the track width direction (X direction in the drawing) of the insulating layer 30 are referred to as both side regions B. .

  As shown in FIGS. 1 and 2, a return yoke layer 27, which is a second magnetic layer made of a magnetic material such as permalloy, is formed on the front region A, the insulating layer 30, and the both side regions B. ing. As shown in FIG. 1, the rear end of the return yoke layer 27 in the height direction is a connection portion 27 c that is magnetically connected to the main magnetic pole layer 24. The return yoke layer 27 is covered with a protective layer 31 made of an inorganic insulating material or the like. Note that the second magnetic layer may be a layer that does not have the connecting portion 27c, that is, a magnetic layer that has a main magnetic pole and has no magnetic coupling and has a simple shielding function. The return yoke layer 27 is formed wider in the track width direction than the main pole.

  The return yoke layer 27 is formed by a central portion 27a and both end portions 27b located on both sides of the central portion 27a in the track width direction (X direction in the drawing). The central portion 27a is formed at a position facing the main magnetic pole layer 24 in the film thickness direction (Z direction in the drawing). As shown in FIGS. 1 and 2, the central portion 27 a is formed with a protruding portion 27 a 1 that protrudes upward from the insulating layer 30 to the front region A. The return yoke layer 27 formed on the insulating layer 30 is formed so as to protrude from the return yoke layer 27 formed on the both side regions B because the insulating layer 30 is formed so as to be higher than the both side regions B in the first place. The At this time, the film thickness of the return yoke layer 27 formed on the insulating layer 30 and the film thickness of the return yoke layer 27 formed on both side regions B do not change much. The thickness of the return yoke layer 27 is preferably 0.1 μm to 1.0 μm in consideration of suppressing the PTP phenomenon.

  As shown in FIG. 3, the return yoke layer 27 in the perpendicular magnetic recording head according to the present invention overlaps with the main magnetic pole layer 24 and the surface exposed to the medium facing surface extends in the track width direction. It has an opening 27d extending to the back side. The PTP phenomenon which is the subject of the present invention is a phenomenon caused not by the influence of heat generated by coil energization but by the influence of the external environment. If there is an influence of heat generation by energizing the coil, it can be solved by providing a path to release heat, but in the case of the influence of the external environment, the effect of reducing the influence of heat can be achieved even if a path to release heat is provided It is considered low. The present invention pays attention to this point and the point that the PTP phenomenon is caused by the difference in thermal expansion coefficient between the constituent material of the shield layer and the surrounding insulating material, and the like, the shield layer such as the return yoke layer 27. It has been found that reducing the volume of the material is effective in suppressing the PTP phenomenon. In this case, simply reducing the thickness of the shield layer such as the return yoke layer 27 uniformly reduces the area of the return yoke layer 27 exposed at the medium facing surface and magnetizes the return yoke layer in the height direction. As a result, Edge Write occurs. In consideration of this, the present inventors can suppress the PTP phenomenon by providing an opening in the return yoke layer to reduce the volume of the shield layer, and can provide a highly reliable vertical in a reduced pressure environment. The present inventors have found that a magnetic recording head device can be realized and have reached the present invention.

  In this case, since the magnetic layer such as the return yoke layer 27 is wider than the main magnetic pole layer 24 and has sufficient thickness and depth, there is a degree of freedom in providing the opening 27d. Therefore, the position and size of the opening 27d are determined in consideration of suppressing the PTP phenomenon while the return yoke layer 27 exhibits a sufficient shielding effect on the main magnetic pole layer 24. That is, the opening 27 d is provided in a region that does not affect the magnetic relationship between the main magnetic pole layer 24 and the return yoke layer 27 in the front portion 24 a of the main magnetic pole layer 24. Therefore, the return yoke layer 27 sufficiently shields the front portion 24a of the main magnetic pole layer 24 at a position where magnetic characteristics required for perpendicular magnetic recording can be maintained, that is, the main magnetic pole layer 24 does not absorb magnetic flux. An opening 27d is provided at a position where the magnetic flux is saturated in the return yoke layer 27 covering the front portion 24a so that the magnetic flux does not leak to the outside. Therefore, the opening 27d is provided away from the front portion 24a of the main magnetic pole layer 24 by a sufficient distance to satisfy the above requirement.

  In consideration of such requirements, the opening 27d is formed to extend deeper in the height direction than the position where the width of the main pole in the track width direction is narrowed in plan view. FIG. 4 is a schematic view of the main magnetic pole layer 24 in plan view. As shown in FIG. 4, in the main magnetic pole layer 24, the main magnetic pole gradually becomes narrower toward the medium facing surface (upper side in FIG. 4) at the first corner 24c, and further the second corner (neck). Part) 24b, the main magnetic pole is narrowed to form the front part 24a. Here, the position where the width of the main magnetic pole in the track width direction is reduced in plan view means the first corner portion 24c and the second corner portion 24b. Therefore, the opening 27d of the return yoke layer 27 extends in the height direction rear side (C direction in FIG. 4) from the first corner 24c and the second corner 24b (so-called opening start portion) in plan view. To be formed.

  In order to exert a better shielding effect on the main magnetic pole layer 24 of the return yoke layer 27, it is preferable to set the opening start portion to the first corner portion 24c in plan view. In the present embodiment, the shape of the main magnetic pole layer 24 on the back side in the height direction from the neck portion is not limited to the shape shown in FIGS. 2 and 4 and can be variously modified. That is, in the present embodiment, the shape in which the shape of the main magnetic pole layer 24 is narrowed in two steps in the region including the front portion 24a is described, but the present invention is not limited to this, The region including the front portion 24a of the main magnetic pole layer 24 may be gradually narrowed in three or more steps, or may be gradually narrowed without having a corner portion over the front portion 24a.

  As an example of the size of the opening 27d, an opening start portion of 0.1 μm to 3 μm from the medium facing surface to the back side in the height direction has a width of 1 μm to 30 μm and a depth of 1 μm to 10 μm. It is preferable.

  When the shield layer is the return yoke layer 27, it is preferable that the opening 27d is formed up to a position (opening end point) that does not reach the connecting portion 27c existing on the deeper side in the height direction than the medium facing surface. . When the shield layer is the lower shield layer 13 or the upper shield layer 16, there is no restriction on the position of the opening end point of the opening.

  Thus, in the perpendicular magnetic recording head in which the return yoke layer 27 is formed with the opening 27d extending in the depth direction from the position where the width of the main pole in the track width direction is narrowed in plan view. Since the volume of the return yoke layer 27 is relatively small, it is possible to reduce the influence of the difference in thermal expansion coefficient between the constituent material of the return yoke layer 27 and the constituent materials of the surrounding layers. PTP phenomenon can be suppressed.

Next, examples performed for clarifying the effects of the present invention will be described.
1 has the basic structure shown in FIG. 1, and the return yoke layer 27 has an opening 27d (an opening start portion of 1.0 μm from the medium facing surface to the back in the height direction, the width is 20.0 μm, and the depth is 9). Thermal analysis of a perpendicular magnetic recording head (Example) having a thickness of 0.0 μm and a perpendicular magnetic recording head (Comparative Example) having the basic structure shown in FIG. The amount of protrusion of the element protruding from the medium facing surface by heat was determined by simulation. The protruding amount of the element was measured at the central portion in the track width direction near the main magnetic pole and the edge portion near the thick film portion. The result is shown in FIG.

  As can be seen from FIG. 5, the perpendicular magnetic recording head (Example) having an opening in the return yoke layer had an element protrusion amount in the vicinity of the trailing side end face (trailing edge) 10b of about 2.1 nm. In the perpendicular magnetic recording head (comparative example) having no opening in the return yoke layer, the element protrusion amount in the vicinity of the trailing edge was about 2.8 nm. That is, it was found that the amount of protrusion of the element near the trailing edge was reduced by about 25%.

  As described above, when the amount of protrusion of the element increases due to the PTP phenomenon, when the head flying height decreases in a reduced pressure environment, the distance between the medium and the head occurs, and the reliability of magnetic recording decreases. In this case, a difference occurs in the decompression characteristics between normal temperature and high temperature. Here, by using an AE sensor (Pico AE sensor, manufactured by PHYSICAL ACOUSTICS CORPORATION) in a perpendicular magnetic recording head device, the pressure when the head and the medium come into contact under a reduced pressure at room temperature (25 ° C.), and a high temperature (60 ° C.). The pressure when the head and the medium contact with each other under reduced pressure was measured. The result is shown in FIG.

  As can be seen from FIG. 6, as the amount of protrusion of the element increases due to the PTP phenomenon, the pressure reduction characteristics deteriorate, that is, the difference in pressure reduction characteristics between normal temperature and high temperature increases. Specifically, the depressurization characteristic of 0.05 atm was deteriorated by the increase in the protruding amount of the element of 1 nm. Therefore, in the perpendicular magnetic recording head device according to the present invention, the amount of protrusion of the element in the PTP phenomenon can be reduced by about 25%, so that the deterioration of the decompression characteristic can be suppressed, and excellent magnetic recording reliability can be achieved. Showing gender.

  The overwrite characteristics of the perpendicular magnetic recording heads of the above examples and comparative examples were examined. The result is shown in FIG. The overwrite characteristics were evaluated by cross track performance. The cross track performance was evaluated by comparing the magnetic field strength between the example and the comparative example by magnetic field simulation. As can be seen from FIG. 7, the overwrite characteristic of the perpendicular magnetic recording head of the example is almost the same as the overwrite characteristic of the perpendicular magnetic recording head of the comparative example, and the magnetic characteristic is that an opening is provided in the return yoke layer. Has no effect. This is presumably because a magnetic circuit is formed in the return yoke layer other than the opening.

  Although the case where the coil is a solenoid coil has been described in the above embodiment, the present invention can also be applied to the case where the coil is a spiral coil. As described above, the PTP phenomenon is a phenomenon caused by the influence of the external environment, not the influence of heat generation due to coil energization. For this reason, since it is considered that the PTP phenomenon occurs even if the coil forms are different, the present invention is also effective when the coil is a spiral coil.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications. For example, in the above embodiment, the case where the magnetic layer having the shielding effect is the return yoke layer is described, but the present invention is the case where the magnetic layer having the shielding effect is the lower shield layer or the upper shield layer. It can also be applied to. Moreover, there is no restriction | limiting in particular about the numerical value and material which were demonstrated in the said embodiment, and the shape of a member. Other modifications may be made as appropriate without departing from the scope of the object of the present invention.

1 is a longitudinal sectional view showing a magnetic head including a perpendicular magnetic recording head according to an embodiment of the present invention. FIG. 2 is a partial plan view of the perpendicular magnetic recording head shown in FIG. 1 and a partial front view of a return yoke layer. FIG. 2 is a perspective view showing a return yoke layer of the perpendicular magnetic recording head shown in FIG. 1. It is a figure which shows the planar view state of the main magnetic pole layer. It is a figure which shows the element protrusion amount in a perpendicular magnetic recording head. It is a figure which shows the relationship between element protrusion amount and pressure_reduction | reduced_pressure characteristic deterioration. It is a figure which shows the overwrite characteristic in a perpendicular magnetic recording head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Slider 12 Nonmagnetic insulating layer 13 Lower shield layer 14 Reading element 15 Inorganic insulating layer 16 Upper shield layer 18 Lower layer coil piece 21 Gap layer 23 Upper layer coil piece 24 Main magnetic pole layer 24a Front part 24b, 24c Corner part 26 Coil insulation layer 27 Return yoke layer 27c Connection portion 27d Opening portion 28 Spacing adjustment insulating layer

Claims (3)

  A first magnetic layer having a main magnetic pole exposed at a surface facing the recording medium, a second magnetic layer provided to the magnetic layer via a nonmagnetic layer and wider than the main magnetic pole, A coil layer for applying a recording magnetic field to the first magnetic layer, and the second magnetic layer overlaps with the main magnetic pole in a plan view, and a surface exposed to the medium facing surface extends in the track width direction. And a perpendicular magnetic recording head device having an opening extending to the back side in the height direction.   2. The perpendicular magnetic recording head device according to claim 1, wherein the opening extends from the position where the width of the main magnetic pole in the track width direction is narrowed to the back side in the height direction.   2. When the second magnetic layer is a return yoke layer, the opening is formed up to a position that does not reach a connecting portion that is located on the deeper side in the height direction than the facing surface. Alternatively, the perpendicular magnetic recording head device according to claim 2.

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