Spin torque oscillator with low magnetic moment and high perpendicular magnetic anisotropy material

Patent metadata

Field	Value
Publication number	US-9378759-B2
Application number	US-201414548853-A
Country	US
Kind code	B2
Filing date	Nov 20, 2014
Priority date	Nov 20, 2014
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

Embodiments disclosed herein generally relate to a magnetic disk device employing a MAMR head. The MAMR head includes an STO. The STO comprises an underlayer, an SPL, an interlayer, an FGL, and a capping layer. The SPL is comprised of a high perpendicular magnetic anisotropy material. The SPL has a large effective perpendicular magnetic anisotropy field, and the SPL has a lower magnetic moment than the FGL. An applied current is adapted to flow in a direction from the FGL to the SPL resulting in the magnetization direction of the SPL being almost perpendicular to the FGL and anti-parallel to a head-gap magnetic field due to a relation between a first spin torque directed from the SPL to the FGL and a second spin torque directed from the FGL to the SPL.

First claim

What is claimed is:

1. A spin torque oscillator, comprising:
an underlayer;
a spin polarization layer comprised of a high perpendicular magnetic anisotropy material, the spin polarization layer having a large effective perpendicular magnetic anisotropy field;
an interlayer;
a field generation layer; and
a capping layer;
wherein a coil is adapted to generate a head-gap field; and
wherein a power supply is adapted to apply a current to flow in a direction from the field generation layer to the spin polarization layer resulting in a magnetization direction of the spin polarization layer anti-parallel to the head-gap field, and wherein the spin polarization layer has a lower magnetic moment than the field generation layer, wherein the spin polarization layer has a magnetic moment lower than about 1 T and the field generation layer has a magnetic moment greater than about 1 T.

2. The spin torque oscillator of claim 1 , wherein the spin polarization layer is disposed on the underlayer, the interlayer is disposed on the spin polarization layer, the field generation layer is disposed on the interlayer, and the capping layer is disposed between the field generation layer and a trailing shield.

3. The spin torque oscillator of claim 1 , wherein the field generation layer is disposed on the underlayer, the interlayer is disposed on the field generation layer, the spin polarization layer is disposed on the interlayer, and the capping layer is disposed between the spin polarization layer and a trailing shield.

4. A spin torque oscillator, comprising:
an underlayer;
a spin polarization layer comprised of a high perpendicular magnetic anisotropy material, the spin polarization layer having a large effective perpendicular magnetic anisotropy field;
an interlayer;
a field generation layer; and
a capping layer;
wherein a coil is adapted to generate a head-gap field; and
wherein a power supply is adapted to apply a current to flow in a direction from the field generation layer to the spin polarization layer resulting in a magnetization direction of the spin polarization layer anti-parallel to the head-gap field, and wherein the spin polarization layer has a lower magnetic moment than the field generation layer, wherein an effective perpendicular magnetic anisotropy field of the spin polarization layer is greater than 10 kOe.

5. The spin torque oscillator of claim 4 , wherein the high perpendicular magnetic anisotropy material comprising the spin torque oscillator is a magnetic alloy structure containing Co, Ni, or Fe.

6. The spin torque oscillator of claim 4 , wherein the high perpendicular magnetic anisotropy material comprising the spin torque oscillator is a magnetic multilayer structure selected from the group consisting of Co, Ni and Fe and their respective alloys with a non-magnetic material selected from the group consisting of Pd, Pt, Ir, Rh and Cu.

7. The spin torque oscillator of claim 6 , wherein the high perpendicular magnetic anisotropy material comprising the spin torque oscillator is [Co/Pd]n, [Co/Pt]n, [Ni/Pd]n, [FeCo/Pd]n, [CoNi/Pd]n, [Fe/Pt]n, or [Co/Ni]n, where n is an integer from 2 to 6.

8. A spin torque oscillator, comprising:
an underlayer;
a spin polarization layer comprised of a high perpendicular magnetic anisotropy material, the spin polarization layer having a large effective perpendicular magnetic anisotropy field;
an interlayer;
a field generation layer; and
a capping layer;
wherein a coil is adapted to generate a head-gap field; and
wherein a power supply is adapted to apply a current to flow in a direction from the field generation layer to the spin polarization layer resulting in a magnetization direction of the spin polarization layer anti-parallel to the head-gap field, and wherein the spin polarization layer has a lower magnetic moment than the field generation layer, wherein the high perpendicular magnetic anisotropy material comprising the spin torque oscillator is one material selected from the group consisting of Fe, Co and FeCo combined with one material selected from the group consisting of Gd, Tb, Dy, Ho, and Er.

9. A magnetic head, comprising:
a main pole;
a coil adapted to excite the main pole, wherein the coil is adapted to generate a head-gap field;
a trailing shield; and
a spin torque oscillator disposed between the main pole and the trailing shield, comprising:
an underlayer disposed on the main pole;
a field generation layer;
an interlayer;
a spin polarization layer disposed on the interlayer, wherein the spin polarization layer is comprised of a high perpendicular magnetic anisotropy material, and wherein the spin polarization layer has a large effective perpendicular magnetic anisotropy field; and
a capping layer disposed under the trailing shield;

wherein a power supply is adapted to apply a current to the spin torque oscillator, wherein the current is adapted to flow in a direction from the field generation layer to the spin polarization layer resulting in a magnetization direction of the spin polarization layer anti-parallel to the head-gap field, and wherein the spin polarization layer has a lower magnetic moment than the field generation layer, wherein the spin polarization layer has a magnetic moment lower than about 1 T and the field generation layer has a magnetic moment greater than about 1 T.

10. The magnetic head of claim 9 , wherein the power supply is adapted to apply a current to the coil to reverse the direction of the head-gap field.

11. The magnetic head of claim 9 , wherein the spin polarization layer is disposed on the underlayer, the interlayer is disposed on the spin polarization layer, the field generation layer is disposed on the interlayer, and the capping layer is disposed between the field generation layer and the trailing shield.

12. The magnetic head of claim 9 , wherein the field generation layer is disposed on the underlayer, the interlayer is disposed on the field generation layer, the spin polarization layer is disposed on the interlayer, and the capping layer is disposed between the spin polarization layer and the trailing shield.

13. The magnetic head of claim 9 , wherein the high perpendicular magnetic anisotropy material comprising the spin torque oscillator is a magnetic multilayer structure selected from the group consisting of Co, Ni and Fe and their respective alloys with a non-magnetic material selected from the group consisting of Pd, Pt, Ir, Rh and Cu.

14. The magnetic head of claim 13 , wherein the high perpendicular magnetic anisotropy material comprising the spin torque oscillator is [Co/Pd]n, [Co/Pt]n, [Ni/Pd]n, [FeCo/Pd]n, [CoNi/Pd]n, [Fe/Pt]n, or [Co/Ni]n, where n is an integer from 2 to 6.

15. The magnetic head of claim 9 , wherein the high perpendicular magnetic anisotropy material comprises CoFe, Coir, CoCr, CoCrPt, CoPt, or FePt.

16. A magnetic head, comprising:
a main pole;
a coil adapted to excite the main pole, wherein the coil is adapted to generate a head-gap field;
a trailing shield; and
a spin torque oscillator disposed between the main pole and the trailing shield, comprising:
an underlayer disposed on the main pole;
a field generation layer;
an interlayer;
a spin polarization layer disposed on the interlayer, wherein the spin polarization layer is comprised of a high perpendicular magnetic anisotropy material, and wherein the spin polarization layer has a large effective perpendicular magnetic anisotropy field; and
a capping layer disposed under the trailing shield;

wherein a power supply is adapted to apply a current to the spin torque oscillator, wh

Assignees

• HGST Netherlands BV

Inventors

• Nagasaka Keiichi
• Sato Yo
• Sato Masashige
• Okamura Susumu
• Shiimoto Masato
• Igarashi Masukazu

Classifications

• G11B5/314 Primary

  where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers (G11B5/3196 takes precedence) · CPC title

• G11B2005/0024

  Microwave assisted recording · CPC title

• G11B5/35 Primary

  having vibrating elements · CPC title

• G11B5/00 Primary

  Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor (G11B11/00 {and G11B13/00} take precedence) · CPC title

• G11B5/607

  using thermal means · CPC title