# US 2015/0103431 A1 · Sto with anti-ferromagnetic coupling interlayer

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- Number: US 2015/0103431 A1
- Document ID: US20150103431A1
- Status: Published application
- Kind: A1
- Application number: 14/052,370
- Filed: 2013-10-11
- Published: 2015-04-16
- Earliest claimed: 2013-10-11
- Assignees: HGST Netherlands B.V.
- Applicants: HGST Netherlands B.V.
- Inventors: Masukaza IGARASHI; Keiichi NAGASAKA; Masato SHIIMOTO
- Web page: https://patentgrep.com/patent/US20150103431A1

## CPC

- G11B 5/3116: {Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks (G11B5/3113, G11B5/245 take precedence)}
- G11B 5/235: Selection of material for gap filler {(G11B5/232 takes precedence)}
- G11B 5/3146: {magnetic layers}
- G11B 2005/0024: {Microwave assisted recording}
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

Embodiments described herein generally relate to a magnetic recording device for recording/reproducing data using the magnetization state of a recording medium. More specifically, embodiments described herein provide an STO structure having an SPL and an FGL with an anti-ferromagnetic coupling interlayer disposed between the SPL and FGL. The anti-ferromagnetic coupling interlayer may enable the STO structure to obtain a high assist effect even when operated with a low conducting current.

## Claims

### Claim 1

A microwave assisted magnetic recording (MAMR) head, comprising:
a main magnetic pole;
a trailing shield;
a spin-torque oscillator (STO) disposed between the main magnetic pole and the trailing shield, the STO comprising:
a first magnetic layer;
an anti-ferromagnetic coupling interlayer; and
a second magnetic layer, wherein the first magnetic layer, the anti-ferromagnetic coupling interlayer, and the second magnetic layer are laminated in order from the main magnetic pole, and wherein an anti-ferromagnetic coupling energy of the first magnetic layer and the second magnetic layer is between about −0.2 erg/cm2 and about −4.0 erg/cm2.

### Claim 2 (depends on 1)

The MAMR head of claim 1, wherein a film thickness of the first magnetic layer is thinner than a film thickness of the second magnetic layer.

### Claim 3 (depends on 2)

The MAMR head of claim 2, wherein the film thickness of the first magnetic layer is between about 2.5 nm and about 4.5 nm.

### Claim 4 (depends on 3)

The MAMR head of claim 3, wherein the first magnetic layer comprises Co and/or Ni.

### Claim 5 (depends on 3)

The MAMR head of claim 3, wherein the film thickness of the second magnetic layer is between about 5 nm and about 15 nm.

### Claim 6 (depends on 5)

The MAMR head of claim 5, wherein the second magnetic layer comprises CoFe.

### Claim 7 (depends on 2)

The MAMR head of claim 2, wherein a conduction direction of the STO is from the trailing shield to the main magnetic pole.

### Claim 8 (depends on 2)

The MAMR head of claim 2, wherein the first magnetic layer and the second magnetic layer are anti-ferromagnetically coupled through the anti-ferromagnetic coupling layer.

### Claim 9 (depends on 1)

The MAMR head of claim 1, wherein a film thickness of the first magnetic layer is thicker than the second magnetic layer.

### Claim 10 (depends on 9)

The MAMR head of claim 9, wherein the film thickness of the first magnetic layer is between about 5 nm and about 15 nm.

### Claim 11 (depends on 10)

The MAMR head of claim 10, wherein the first magnetic layer comprises CoFe.

### Claim 12 (depends on 10)

The MAMR head of claim 10, wherein the film thickness of the second magnetic layer is between about 2.5 nm and about 4.5 nm.

### Claim 13 (depends on 12)

The MAMR head of claim 12, wherein the second magnetic layer comprises Co and/or Ni.

### Claim 14 (depends on 9)

The MAMR head of claim 9, wherein a conduction direction of the STO is from the main magnetic pole to the trailing shield.

### Claim 15 (depends on 9)

The MAMR head of claim 9, wherein the first magnetic layer and the second magnetic layer are anti-ferromagnetically coupled through the anti-ferromagnetic coupling layer.

### Claim 16 (depends on 1)

The MAMR head of claim 1, wherein a film thickness of the anti-ferromagnetic coupling layer is between about 0.4 nm to about 1.5 nm.

### Claim 17 (depends on 1)

The MAMR head of claim 1, wherein the anti-ferromagnetic coupling layer is selected from the group consisting of Ru, Cr, Cu, Rh, and Ir.

### Claim 18 (depends on 1)

The MAMR head of claim 1, wherein the STO further comprises an underlayer and a cap layer.

### Claim 19 (depends on 2)

The MAMR head of claim 2, wherein the first magnetic layer has a plane of easy magnetization in a first magnetic layer plane.

### Claim 20 (depends on 9)

The MAMR head of claim 9, wherein the second magnetic layer has a plane of easy magnetization in a second magnetic layer plane.