Extended spin torque oscillator

Patent metadata

Field	Value
Publication number	US-9336797-B2
Application number	US-201414290768-A
Country	US
Kind code	B2
Filing date	May 29, 2014
Priority date	May 29, 2014
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

The present disclosure generally relates to a high-frequency oscillator for use in a recording device having a microwave-assisted magnetic recording head. The microwave-assisted magnetic recording head achieves a large assist effect by using an extended spin torque oscillator disposed between a main magnetic pole and a pole opposite the main magnetic pole. The spin torque oscillator obtains a strong high-frequency magnetic field and comprises a first non-magnetic spin scatterer, a reference layer, a first non-magnetic spin transfer layer, a first magnetic field generating layer, a second non-magnetic spin transfer layer, a second magnetic field generating layer, and a second non-magnetic spin scatterer. The spin torque oscillator has a drive current flowing though in the direction from the first magnetic field generating layer to the reference layer.

First claim

What is claimed is:

1. A microwave-assisted magnetic recording head, comprising:
a main magnetic pole;
a magnetic pole opposite the main magnetic pole; and
a spin torque oscillator disposed between the main magnetic pole and the magnetic pole opposite the main magnetic pole, wherein the spin torque oscillator is comprised of: a first non-magnetic spin scatterer in physical contact with either the main magnetic pole or the magnetic pole opposite the main magnetic pole, a reference layer in physical contact with the first non-magnetic spin scatterer, a first non-magnetic spin transfer layer in physical contact with the reference layer, a first magnetic field generating layer in physical contact with the first non-magnetic spin transfer layer, a second non-magnetic spin transfer layer in physical contact with the first magnetic field generating layer, a second magnetic field generating layer in physical contact with the second non-magnetic spin transfer layer, and a second non-magnetic spin scatterer in physical contact with the second magnetic field generating layer, wherein the second non-magnetic spin scatterer is in physical contact with either the main magnetic pole or the magnetic pole opposite the main magnetic pole, and wherein:
the first magnetic field generating layer is thicker than the second magnetic field generating layer; and
a drive current flows in the direction from the first magnetic field generating layer to the reference layer.

2. The microwave-assisted magnetic recording head of claim 1 , wherein the second magnetic field generating layer is 3 nanometers to 5 nanometers thick.

3. The microwave-assisted magnetic recording head of claim 2 , wherein the first magnetic field generating layer is the thickest layer in the spin torque oscillator.

4. The microwave-assisted magnetic recording head of claim 1 , wherein the first magnetic field generating layer has a larger saturated magnetization when compared to the second magnetic field generating layer.

5. The microwave-assisted magnetic recording head of claim 4 , wherein the second field generating layer has a saturated magnetization of at least 1.6 Teslas.

6. The microwave-assisted magnetic recording head of claim 1 , wherein the spin torque oscillator comprises in order from the main magnetic pole to the pole opposite the main magnetic pole: the second non-magnetic spin scatterer, the second magnetic field generating layer, the second non-magnetic spin transfer layer, the first magnetic field generating layer, the first non-magnetic spin transfer layer, the reference layer, and the first non-magnetic spin scatterer.

7. The microwave-assisted magnetic recording head of claim 1 , wherein the first magnetic field generating layer and the second magnetic field generating layer comprise cobalt-iron alloy.

8. The microwave-assisted magnetic recording head of claim 1 , wherein the reference layer comprises a nickel film.

9. The microwave-assisted magnetic recording head of claim 1 , wherein the first non-magnetic spin scatterer or the second non-magnetic spin scatterer comprises ruthenium.

10. A microwave-assisted magnetic recording head, comprising:
a main magnetic pole;
a magnetic pole opposite the main magnetic pole; and
a spin torque oscillator disposed between the main magnetic pole and the magnetic pole opposite the main magnetic pole, wherein the spin torque oscillator is comprised of: a first non-magnetic spin scatterer, a reference layer, a first non-magnetic spin transfer layer, a first magnetic field generating layer, a second non-magnetic spin transfer layer, a second magnetic field generating layer, and a second non-magnetic spin scatterer, wherein the spin torque oscillator comprises in order from the main magnetic pole to the pole opposite the main magnetic pole; the second non-magnetic spin scatterer, the second magnetic field generating layer, the second non-magnetic spin transfer layer, the first magnetic field generating layer, the first non-magnetic spin transfer layer, the reference layer, and the first non-magnetic spin scatterer, wherein the first non-magnetic spin transfer layer comprises nickel-aluminum, and wherein
the first magnetic field generating layer is thicker than the second magnetic field generating layer; and
a drive current flows in the direction from the first magnetic field generating layer to the reference layer.

11. The microwave-assisted magnetic recording head of claim 10 , wherein the second non-magnetic spin transfer layer is thinner than 1 nanometer.

12. The microwave-assisted magnetic recording head of claim 10 , wherein the main magnetic pole and the pole opposite the main magnetic pole comprise a cobalt-iron alloy.

13. The microwave-assisted magnetic recording head of claim 10 , wherein the first magnetic field generating layer has a larger saturated magnetization than the second magnetic field generating layer.

14. The microwave-assisted magnetic recording head of claim 10 , wherein the second magnetic field generating layer is 3 nanometers to 5 nanometers thick.

15. The microwave-assisted magnetic recording head of claim 10 , wherein the first non-magnetic spin transfer layer or the second non-magnetic spin transfer layer comprises copper.

16. The microwave-assisted magnetic recording head of claim 10 , wherein the first magnetic field generating layer is the thickest layer of the spin torque oscillator, a drive current flows in the direction from the pole opposite the main magnetic pole to the main magnetic pole, and the second non-magnetic spin transfer layer is the thinnest layer of the spin torque oscillator.

17. A hard disk drive, comprising:
a rotary actuator;
an arm;
a magnetic head slider;
a recording and playback unit disposed on the magnetic head slider;
a microwave-assisted magnetic recording head;
a main magnetic pole disposed on the recording and playback unit;
a magnetic pole opposite the main magnetic pole disposed on the recording and playback unit; and
a spin torque oscillator disposed between the main magnetic pole and the magnetic pole opposite the main magnetic pole, wherein the spin torque oscillator is comprised of: a first non-magnetic spin scatterer in physical contact with either the main magnetic pole or the magnetic pole opposite the main magnetic pole, a reference layer in physical contact with the first non-magnetic spin scatterer, a first non-magnetic spin transfer layer in physical contact with the reference layer, a first magnetic field generating layer in physical contact with the first non-magnetic spin transfer layer, a second non-magnetic spin transfer layer in physical contact with the first magnetic field generating layer, a second magnetic field generating layer in physical contact with the second non-magnetic spin transfer layer, and a second non-magnetic spin scatterer in physical contact with the second magnetic field generating layer, wherein the second non-magnetic spin scatterer is in physical contact with either the main magnetic pole or the magnetic pole opposite the main magnetic pole, and wherein:
the first magnetic field generating layer is thicker than the second magnetic field generating layer; and
a drive current flows in the direction from the first magnetic field generating layer to the reference layer.

18. The hard disk drive of claim 17 , wherein the recording and playback unit is disposed on the trailing side of the magnetic head slider.

19. The hard disk drive of claim 17 , wherein the recording and playback unit is disposed on the leading side of the ma

Assignees

• HGST Netherlands BV

Inventors

• Igarashi Masukazu
• Matsubara Masato
• Nagasaka Keiichi
• Sato Yo
• Shiimoto Masato
• Sato Masashige

Classifications

• G11B5/1278 Primary

  specially adapted for magnetisations perpendicular to the surface of the record carrier · 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

• G11B2005/0024

  Microwave assisted recording · CPC title

• G11B5/235

  Selection of material for gap filler {(G11B5/232 takes precedence)} · CPC title

• G11B5/3146

  magnetic layers · CPC title