JP2012209005A - Magnetic head and magnetic storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic head able to detect a magnetic field leaking from a recording medium without causing a sensing current to flow and able to cope with a high recording density medium.SOLUTION: The magnetic head comprises: a magnetization fixed part 51 in which magnetization is fixed; a magnetization free part 52 joined to the magnetization fixed part and changed in magnetization by an external magnetic field; and a pair of output terminals 56 and 57 connected to the magnetization fixed part and magnetization free part, one for each. A joint part 53 joining the magnetization fixed part and the magnetization free part composes a magnetic wall trap. Using a spin electromotive force resulting from the movement of a magnetic wall in the magnetization free part, a change in the external magnetic field is detected.

Description

  The present invention relates to a magnetic head and a magnetic storage device equipped with the magnetic head.

Magnetic recording devices are becoming higher in recording density year by year, and a reproducing head corresponding to the higher recording density is required. In order to meet this demand, a CIP-GMR (Current in Plane-Giant Magneto-resistance) sensor is used in which a current flows in the surface of a magnetoresistive film formed by sandwiching a thin nonmagnetic layer between two types of ferromagnetic layers. Has been developed and applied as a read head. At present, a TMR (Tunneling Magneto-Resistive) head that uses a current flowing in the film thickness direction of a laminated film and a CPP (Current Perpendicular to the Plane) -GMR head are being transferred. In order to increase the reproduction output, it is common to increase the MR (Magneto-Resistive) ratio. At present, TMR heads with the highest MR ratio are widely used.
As another technique, Patent Document 2 discloses a memory device that uses the movement of a domain wall in a nanostructure made of a magnetic material having electron conductivity.

JP 2003-204096 Gazette WO 2007/015475 A1

Along with the increase in recording density of magnetic recording media, a magnetic reproducing head capable of supporting a magnetic recording medium having a surface recording density of about ² Tb / inch ² will be required in the future. In the case of a magnetic recording medium having a surface recording density of ² Tb / inch ² , the area per bit on the medium surface is estimated to be about 17 × 17 nm ² . Therefore, it is necessary to reduce the size of the reproducing element provided in the magnetic reproducing head to the same size as the medium facing surface.

  In the TMR head and the CPP-GMR head, it is necessary to flow a sense current in order to detect a resistance change due to a leakage magnetic field from the medium. When a current is passed through the magnetic material, as described in Patent Document 2, the magnetization of the magnetic material is affected by the spin of conduction electrons. That is, a force that changes the magnetization of the magnetization free layer in the magnetoresistive film acts by the sense current itself. When the element part of the TMR head or CPP-GMR head is miniaturized as described above, the force that the conduction electrons of the sense current act on the magnetization free layer causes the leakage magnetic field from the recording bit of the medium to act on the magnetization free layer. It may antagonize the force and adversely affect the detection of the recording magnetization of the medium.

  The present invention provides a magnetic head capable of detecting a leakage magnetic field from a recording medium without flowing a sense current and adapting to a high recording density medium based on a new principle.

In the present invention, the change in the external magnetic field is detected using the spin electromotive force accompanying the movement of the domain wall in the magnetic material without flowing a sense current.
The reproducing element used in the magnetic head of the present invention is connected to the magnetization fixed portion with fixed magnetization, the magnetization free portion joined to the magnetization fixed portion and changed in magnetization by an external magnetic field, and the magnetization fixed portion and the magnetization free portion, respectively. A pair of output terminals. The junction between the magnetization fixed part and the magnetization free part constitutes a domain wall trap.

Since the reproducing element of the present invention can detect a change in the magnetic field without passing a sense current, there is no influence of the interaction between the spin of the conduction electron and the magnetic substance spin, and the magnetization information can be read stably.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a cross-sectional view of a magnetic head according to an embodiment of the present invention. The schematic diagram which shows the structural example of a microwave generator. The schematic diagram which shows an example of the reproducing | regenerating element by this invention. The figure explaining the principle of the magnetic field detection by the reproducing | regenerating element of this invention. The schematic diagram explaining the relationship between the recording magnetization of a medium, and the output from the reproducing element of this invention. Explanatory drawing of the other Example of the reproducing | regenerating element by this invention. Explanatory drawing of the other Example of the reproducing | regenerating element by this invention. Explanatory drawing of the other Example of the reproducing | regenerating element by this invention. Explanatory drawing of the other Example of the reproducing | regenerating element by this invention. Explanatory drawing of the other Example of the reproducing | regenerating element by this invention. 1 is a schematic diagram of a magnetic storage device.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a magnetic head according to an embodiment of the present invention. The magnetic head includes a recording head 10 and a reproducing head 20. In the recording head 10, a pillar 13 and an insulator 14 made of a magnetic material are disposed between a main magnetic pole 11 and an auxiliary magnetic pole 12. The main magnetic pole 11, the auxiliary magnetic pole 12, and the pillar 13 are made of a soft magnetic material such as permalloy or a CoFe alloy. The insulator 14 is formed thin enough to magnetically connect the main magnetic pole 11, the auxiliary magnetic pole 12, and the pillar 13. The main magnetic pole 11 is provided with a pole portion 16 in contact with the yoke portion 15. An end surface of the pole portion 16 appears on the head air bearing surface. A trailing shield 17 is provided on the trailing side of the pole portion 16 to make the magnetic field gradient steep. The reproducing head 20 has a reproducing element 21 and a pair of magnetic shields 22 and 23 sandwiching the reproducing element 21. Details of the reproducing element will be described later. In the figure, the arrow LD indicates the reading direction, and the arrow TR indicates the trailing direction.

  A magnetic film constituting the microwave generator 30 is formed on the trailing side of the pole portion 16. The magnetic film constituting the microwave generator 30 irradiates the magnetic recording medium 40 with microwaves locally, thereby exciting magnetic resonance at the irradiated portion and increasing the ease of reversing the magnetization direction. The microwave excitation current flows from the pole portion 16 to the auxiliary magnetic pole 12 through the microwave generator 30. For example, the flow is as indicated by arrows 18a and 18b. As the magnetic recording medium 40, a perpendicular magnetic recording medium can be used.

  FIG. 2 is a schematic diagram illustrating a configuration example of the microwave generator 30. The microwave generator 30 has a structure in which a perpendicular magnetic anisotropy 31, a magnetization high-speed rotator 32, a spin conduction layer 33, a spin injection layer 34, and a spin conduction layer 35 are stacked. The microwave generator 30 is electrically connected to the pole portion 16 of the main magnetic pole and the trailing shield 17, and a microwave excitation current flows from the main magnetic pole side to the trailing shield side or vice versa. As the perpendicular magnetic anisotropy 31, hexagonal CoCrPt or the like is used. For the high-speed magnetization rotator 32, a CoFe alloy or the like having a thickness with a large saturation magnetization and almost no magnetocrystalline anisotropy is used. For the spin conduction layer 35 and the spin conduction layer 33, Ru or Cu, which is a metal nonmagnetic material with high spin conductivity, can be used. For the spin injection layer 34, a perpendicular magnetic anisotropy such as CoPt is used. In the magnetization high-speed rotating body 32, the magnetization rotates at high speed in a plane along the layer, and the leakage magnetic field from the magnetic pole appearing on the air bearing surface acts as a microwave (high-frequency magnetic field).

  The main magnetic pole 11 is excited by a coil 19 wound around a magnetic circuit including the main magnetic pole 11 and the auxiliary magnetic pole 12 and emits a recording magnetic field from the end face of the pole portion 16. The recording magnetic field generated from the pole portion 16 passes through the magnetic recording layer 41 and the intermediate layer 42 of the magnetic disk 40 vertically, passes through the soft magnetic backing layer 43, and is absorbed by the auxiliary magnetic pole 12. The magnetic recording layer 41 is irradiated with the microwave generated from the microwave generator 30 along with the application of the recording magnetic field generated from the pole portion 16, and the recording magnetization is written. The magnetic recording layer 41 has a large magnetic anisotropy, and recording cannot be performed unless the recording magnetic field from the main pole 11 and the microwave magnetic field radiated from the microwave generator 30 are aligned.

  FIG. 3 is a schematic view showing an example of a reproducing element according to the present invention. The reproducing element of the present invention has a structure in which the magnetization fixed portion 51 and the magnetization free portion 52 are joined in a plane. The magnetization fixed portion 51 and the magnetization free portion 52 were formed by depositing permalloy as a magnetic film 55 on a silicon substrate 54 provided with a step. In addition, the magnetization fixed portion 51 and the magnetization free portion 52 are both shaped so that the width gradually decreases toward the junction portion 53, and the junction portion 53 is the narrowest narrow portion. The film thickness of the magnetization fixed part 51 was set larger than the film thickness of the magnetization free part 52 by matching the position of the joint part 53 with the step forming position of the substrate 54. The voltage detection terminals 56 and 57 are typically electrically connected to the upper end portion of the magnetization fixed portion 51 and the lower end portion of the magnetization free portion 52 so as to sandwich the joint portion 53.

  The magnetization of the magnetization fixed part 51 is fixed in one direction and does not change with an external magnetic field. In the case of the illustrated embodiment, the magnetization of the magnetization fixed portion 51 is fixed in the direction connecting the magnetization fixed portion 51 and the magnetization free portion 52. On the other hand, the magnetization of the magnetization free portion 52 can change under the influence of an external magnetic field. The junction 53 between the magnetization fixed part 51 and the magnetization free part 52 constitutes a domain wall trap.

  In this embodiment, the magnetization fixed portion 51 and the magnetization free portion 52 are both formed of permalloy, but may be formed of different magnetic materials. In this embodiment, the magnetization free part 52 has a film thickness of 10 nm, the bottom in the X direction has a length of 25 nm, the Z direction has a length of 100 nm, and the magnetization fixed part 51 has a film thickness of 20 nm and the top in the X direction. Was 60 nm, the length in the Z direction was 300 nm, and the length of the junction 53 in the X direction was 20 nm. The length in the X direction of the joint 53 that requires fine processing is determined by the dimensional limit of the fine processing technology. The thickness of the magnetization free portion 52 is desirably 3 nm or more as the thickness having in-plane anisotropy of magnetization. Another dimension of the magnetization free part 52 is Ku × V = 60, which is known as the superparamagnetic limit (where Ku is the uniaxial anisotropy energy of the magnetic material forming the magnetization free part 52, and V is the magnetization free part 52. It is configured to satisfy the volume of the magnetic material. In consideration of the fact that the domain wall is introduced into the junction 53 and always trapped, it is desirable that the magnetization fixed portion 51 is larger than the magnetization free portion 52. Preferably, the Z dimension of the magnetization fixed portion is set to Z of the magnetization free portion. It is good to set it as about 3 to 5 times the size of.

  The change in the magnetization of the magnetization free part 52 can be considered as a result of the movement of the domain wall in the magnetization free part 52. For example, in the state of FIG. 3, the magnetization fixed part 51 has downward magnetization, the magnetization free part 52 has upward magnetization, and a domain wall exists in the junction part 53 which is a boundary of both. At this time, when a downward external magnetic field is applied to the reproducing element, the domain wall located at the junction 53 moves downward, and the magnetization of the magnetization free portion between the junction 53 and the domain wall moved downward is directed downward from above. Invert. Finally, the domain wall reaches the lower end of the magnetization free portion 52, and the magnetization of the entire magnetization free portion 52 is aligned downward. Next, when an upward external magnetic field is applied in a state where the magnetization of the magnetization fixed portion 51 and the magnetization of the magnetization free portion 52 are aligned downward, a domain wall is generated in the lower end region of the magnetization free portion 52, which is Move upward. When the domain wall moved upward reaches the domain wall trap, it stops there and does not enter the magnetization fixed portion 51 above it. Thus, the magnetization of the magnetization free part 52 returns to the upward state shown in FIG.

FIG. 4 is a diagram for explaining the principle of magnetic field detection by the reproducing element of the present invention.
Here, a reproducing element mounted on a magnetic head for a perpendicular magnetic recording medium will be described. The magnetization free part is arranged on the air bearing surface side of the magnetic head facing the medium, and the magnetization fixed part is arranged at a position farther from the air bearing surface than the magnetization free part. As described above, the change in magnetization of the magnetization free part 52 is the movement of the domain wall in the magnetization free part 52. At this time, the spin at each position in the magnetization free portion 52 rotates but is accompanied by precession due to the magnetic field from the medium and thermal fluctuation. When this spin motion is mapped onto the unit sphere, for example, if the spin rotation start state corresponds to the North Pole and the final state corresponds to the South Pole, the spin motion on the unit sphere draws a geodesic line from the North Pole to the South Pole. Instead, it has a finite solid angle. This solid angle is the Berry phase of the spin, and is a physical quantity for observation as a spin electromotive force.
The spin Berry phase is based on the topological property of the (spin) wave function, but intuitively, the following energy conservation law can be seen. The magnetization of the magnetization free part 52 is directed in a stable direction with low energy by the magnetic field of the medium. In other words, before turning to a stable direction, it was in a state of high energy. This magnetic energy difference is released as electric energy as an electromotive force. When there is no change in the magnetization state of the medium, naturally, the magnetization state of the magnetization free portion 52 does not change, and no electromotive force is detected. In this case, it means that the same signal is recorded in adjacent bits.

FIG. 5 is a schematic diagram for explaining the relationship between the recording magnetization of the medium and the output from the reproducing element of the present invention.
When the magnetic head moves in the direction of the arrow, the magnetization of the magnetization free portion of the reproducing element is affected by the leakage magnetic flux from the recording magnetization recorded on the magnetic recording medium, and is the same as the direction of the recording magnetization immediately below the reproducing element. Change in direction. At that time, an electrical output is obtained according to the principle described with reference to FIG. Thus, in the case of the reproducing element of the present invention, an output is obtained when the recording magnetization of the perpendicular magnetic recording medium travels on the magnetization transition region where the recording magnetization changes from upward to downward or from downward to upward. When the recording magnetization changes from upward to downward and when it changes from downward to upward, the sign of the output signal is reversed as shown in the figure. Since the relationship between the output signal and the recording magnetization is the same as the output of the conventional induction reproducing head, the recording signal can be reproduced by using a circuit equivalent to the circuit used for the signal processing of the induction reproducing head. it can.

  Hereinafter, another embodiment of the reproducing element will be described. The reproducing element shown in FIG. 3 has a structure in which a film thickness difference is provided between the magnetization fixed part and the magnetization free part as a structure for configuring a domain wall trap that stops the movement of the domain wall between the magnetization fixed part and the magnetization free part. This is a combination of a structure in which the junction between the magnetization fixed portion and the magnetization free portion is a narrow constriction portion. However, it is not always necessary to use these structures in combination.

FIG. 6 is an explanatory diagram of another embodiment of a reproducing element according to the present invention.
In the reproducing element of this example, the junction 53 is a domain wall trap by a structure in which the junction 53 of the magnetization fixed portion 51 and the magnetization free portion 52 is the narrowest narrow portion. In this example, the magnetization fixed part 51 and the magnetization free part 52 were formed by depositing a permalloy film of 20 nm as a magnetic film 55 on a flat silicon substrate 54. In addition to permalloy, Fe, Co, Ni, and alloys thereof may be used for the magnetic film 55. The magnetization free portion 52 has a bottom portion with a length in the X direction of 25 nm and a length in the Z direction of 100 nm. The magnetization fixed portion 51 has an upper X-direction length of 60 nm and a Z-direction length of 300 nm. The junction 53 has a length in the X direction of 20 nm. Similar to the description in the structure of FIG. 3, the narrowest part of the device width is the length of the bonding portion 53 in the X direction and is determined by the size limit of the microfabrication technology. In the structure of FIG. 6, the magnetization fixed portion 51 and the magnetization free portion 52 have the same thickness and a thickness having in-plane anisotropy of magnetization.

FIG. 7 is an explanatory diagram of another embodiment of a reproducing element according to the present invention.
In the reproducing element of the present embodiment, a difference in film thickness is provided between the magnetic films of the magnetization fixed portion 51 and the magnetization free portion 52, and a step is formed in the junction 53 so that the junction 53 is a domain wall trap. In this embodiment, the magnetization fixed portion 51 and the magnetization free portion 52 are formed by depositing permalloy as the magnetic film 55 on the silicon substrate 54 on which the step is formed. In addition to permalloy, Fe, Co, Ni, and alloys thereof may be used for the magnetic film 55. The magnetization free part 52 had a film thickness of 20 nm, a length in the X direction of 20 nm, and a length in the Z direction of 100 nm. The magnetization fixed portion 51 has a film thickness of 40 nm, a length in the X direction of 20 nm, and a length in the Z direction of 300 nm. In the structure of FIG. 7, the width of the device (the length in the X direction) is the same, and is determined by the dimensional limit of the microfabrication technology as described in the structure of FIG.

FIG. 8 is an explanatory diagram of another embodiment of a reproducing element according to the present invention.
In the reproducing element of this embodiment, the coercive force of the magnetic film 55a of the magnetization fixed part 51 is set larger than the coercive force of the magnetic film 55b of the magnetization free part 52, whereby the junction part 53 that is a boundary part between the two magnetic films is formed. Is a domain wall trap. In the present embodiment, Co is used as the material of the magnetic film 55a constituting the magnetization fixed portion 51, and Permalloy is used as the material of the magnetic film 55b constituting the magnetization free portion 52. It formed so that it might be set to 20 nm. The magnetocrystalline anisotropy energy (density), which is a measure of the coercive force of the magnetic film 55a, is 50 KJ / m ³ , and the magnetocrystalline anisotropy energy (density) of the magnetic film 55b is almost zero. The magnetic film 55a and the magnetic film 55b may be a combination of other materials as long as they produce a coercive force difference of about 50 Oe or more. For example, Fe and permalloy, or FePt and permalloy may be combined. The magnetization free portion 52 has a length in the X direction of 20 nm and a length in the Z direction of 100 nm. The magnetization fixed portion 51 has a length in the X direction of 20 nm and a length in the Z direction of 200 nm. .

FIG. 9 is an explanatory diagram of another embodiment of the reproducing element according to the present invention.
In the reproducing element of this embodiment, the magnetization fixed portion 51 and the magnetization free portion 52 are bonded not at a straight line but at an angle so that the bent bonded portion 53 is a domain wall trap. In this example, the magnetization fixed part 51 and the magnetization free part 52 were formed by depositing a permalloy film of 20 nm as a magnetic film 55 on a flat silicon substrate 54. In addition to permalloy, Fe, Co, Ni, and alloys thereof may be used for the magnetic film 55. The magnetization free portion 52 has a length in the X direction of 20 nm and a central axis in the Z direction of 100 nm. In the magnetization fixed portion 51, the length of the central axis in the X direction is 200 nm, and the length in the Z direction is 20 nm. In this embodiment, the refraction angle θ formed by the central axis of the magnetization fixed portion 51 and the central axis of the magnetization free portion 52 is 90 degrees. The refraction angle θ is preferably in the range of 60 to 120 degrees.

FIG. 10 is an explanatory diagram of another embodiment of the reproducing element according to the present invention.
In the reproducing element of this example, an antiferromagnetic film is formed as a base film of the magnetic film 55 constituting the magnetization fixed part 51 and the magnetization free part 52. Since the magnetization free portion 52 has a small volume, it becomes thermally unstable, and there is a possibility that the magnetization direction is disturbed and faces a random direction. In the present embodiment, the base film 58 made of an antiferromagnetic film is formed on the substrate 54, and the magnetic film 55 constituting the magnetization fixed portion 51 and the magnetization free portion 52 is formed thereon, whereby the magnetic film 55, In particular, uniaxial anisotropy is imparted to the magnetic film constituting the magnetization free portion 52 to suppress the magnetization direction of the magnetization free portion 52 from becoming thermally unstable. As the antiferromagnetic film, MnIr, MnPt or the like may be formed to a thickness of about 10 nm.

  FIG. 10 shows an example in which the base film 58 made of an antiferromagnetic material is formed on the reproducing element described with reference to FIG. 6. However, in the reproducing element of another embodiment, an antiferromagnetic film is used as the base film of the magnetic film. The same effect can be obtained by using.

  FIG. 11 is a schematic diagram of a magnetic memory device, FIG. 11 (a) is a schematic plan view thereof, and FIG. 11 (b) is a schematic cross-sectional view thereof. This magnetic storage device includes a perpendicular magnetic recording medium 60, a drive unit 61 that rotationally drives it, a magnetic head 62, a voice coil motor 63 that is a drive means thereof, and a recording / reproduction signal processing means 65 of the magnetic head. The magnetic head 62 is the above-described magnetic head of the present invention. The magnetic head 62 is attached to the tip of the gimbal 64 and is driven relative to the perpendicular magnetic recording medium 60 by the voice coil motor 63 to be positioned on a desired track. The recording signal transmitted from the host is sent to the recording head of the magnetic head 62 via the signal processing circuit 65 and recorded on the perpendicular magnetic recording medium 60 by causing magnetization reversal. Further, the leakage magnetic field due to the recording magnetization of the perpendicular magnetic recording medium 60 is detected by the reproducing element of the present invention incorporated in the magnetic head 62, and the detected signal is processed by the signal processing circuit 65 and then sent to the host as a reproduced signal. Sent.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  For example, it is apparent that a reproducing element can be manufactured by appropriately combining the components described in the embodiments of FIGS. Although not described one by one, for example, by applying the configuration shown in FIG. 7 to the reproducing element shown in FIG. 9 and setting the film thickness of the magnetization fixed portion 51 to be larger than the film thickness of the magnetization free portion 52, A reproducing element that operates stably can be obtained. Furthermore, a magnetic film having a larger coercive force than the magnetization free portion 52 may be used for the magnetization fixed portion 51 by applying the configuration shown in FIG.

DESCRIPTION OF SYMBOLS 10 Recording head 11 Main magnetic pole 12 Auxiliary magnetic pole 13 Pillar 14 Insulator 15 Yoke part 16 Pole part 17 Trailing shield 19 Coil 20 Reproducing head 21 Reproducing element 22, 23 Magnetic shield 30 Microwave generator 31 Perpendicular magnetic anisotropy 32 Magnetization high-speed rotating body 33 Spin conduction layer 34 Spin injection layer 35 Spin conduction layer 40 Magnetic recording medium 41 Magnetic recording layer 42 Intermediate layer 43 Soft magnetic backing layer 51 Magnetization fixed part 52 Magnetization free part 53 Junction part 54 Silicon substrate 55 Magnetic film 56 57 Terminal 58 Underlayer

Claims (10)

In a magnetic head comprising a pair of magnetic shields and a reproducing element disposed therebetween,
The reproducing element includes a magnetization fixed portion having fixed magnetization, a magnetization free portion that is joined to the magnetization fixed portion, and whose magnetization is changed by an external magnetic field, and a pair of magnetization connected to the magnetization fixed portion and the magnetization free portion. With output terminal,
The magnetic head according to claim 1, wherein a junction between the magnetization fixed portion and the magnetization free portion constitutes a domain wall trap.   2. The magnetic head according to claim 1, wherein a spin electromotive force associated with the domain wall movement in the magnetization free portion is output.   2. The magnetic head according to claim 1, wherein the joining portion is a narrowed portion having a narrow width.   2. The magnetic head according to claim 1, wherein a film thickness of the magnetic film constituting the magnetization fixed part is larger than a film thickness of the magnetic film constituting the magnetization free part, and the magnetic film of the magnetization fixed part is A magnetic head, wherein a step is formed in the magnetic film of the magnetization free portion.   2. The magnetic head according to claim 1, wherein the coercivity of the magnetic film constituting the magnetization fixed portion is larger than the coercivity of the magnetic film constituting the magnetization free portion.   The magnetic head according to claim 1, wherein the magnetization fixed portion and the magnetization free portion are joined at an angle at the joint.   7. The magnetic head according to claim 1, wherein the magnetic film constituting the magnetization fixed portion and the magnetic film constituting the magnetization free portion are formed on an antiferromagnetic film. Magnetic head characterized by   The magnetic head according to claim 1, wherein a volume of the magnetization fixed portion is larger than a volume of the magnetization free portion.   9. The magnetic head according to claim 1, further comprising: a recording head having a magnetic pole that generates a recording magnetic field and a microwave generator that irradiates microwaves. A perpendicular magnetic recording medium; a medium driving unit that drives the perpendicular magnetic recording medium; a magnetic head that writes and reads information to and from the perpendicular magnetic recording medium; and a desired track of the perpendicular magnetic recording medium. In a magnetic storage device having a head drive unit for positioning to
A magnetic storage device using the magnetic head according to claim 9 as the magnetic head.

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