# US 12,190,919 B2 · Dual FGL and dual SPL spintronic device to reduce perpendicular field at writing location

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- Number: US 12,190,919 B2
- Document ID: US12190919B2
- Status: Granted
- Kind: B2
- Application number: 18/226,109
- Filed: 2023-07-25
- Published: 2024-05-02
- Granted: 2025-01-07
- Earliest claimed: 2022-11-01
- Assignees: Western Digital Technologies, Inc.
- Applicants: Western Digital Technologies, Inc.
- Inventors: Muhammad Asif Bashir; Alexander Goncharov; Zhigang Bai; Masato Shiimoto; Yunfei Ding
- Web page: https://patentgrep.com/patent/US12190919B2

## CPC

- G11B 5/3146: {magnetic layers}
- G11B 5/1278: {specially adapted for magnetisations perpendicular to the surface of the record carrier}
- G11B 5/235: Selection of material for gap filler {(G11B5/232 takes precedence)}
- G11B 5/314: {where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers (G11B5/3196 takes precedence)}
- 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 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

The present disclosure is generally related to a magnetic recording device comprising a magnetic recording head. The magnetic recording head comprises a main pole, a shield, and a spintronic device disposed between the main pole and the shield. The spintronic device comprises two field generation layers (FGLs), two spin polarization layers (SPLs), and two spin kill layers. The spintronic device further comprises one or more optional thin negative beta material layers, such as layers comprising FeCr, disposed in contact with at least one of the spin kill layers. When electric current is applied, the spin kill layers and optional negative beta material layers eliminate or reduce any spin torque between the FGLs and the SPLs.

## Claims

### Claim 1

A magnetic recording head comprising:
a shield;
a main pole; and
a spintronic device disposed between the shield and the main pole, the spintronic device comprising:
a first spin kill layer disposed adjacent to the shield;
a first spin polarization layer disposed between the first spin kill layer and the main pole;
a first field generation layer disposed between the first spin polarization layer and the main pole;
a second spin polarization layer disposed between the first field generation layer and the main pole;
a second spin kill layer disposed between the second spin polarization layer and the main pole;
a first negative beta material layer disposed between the second spin kill layer and the main pole; and
a second field generation layer disposed between the first negative beta material layer and the main pole.

### Claim 2 (depends on 1)

The magnetic recording head of claim 1, wherein the spintronic device further comprises a second negative beta material layer disposed between and in contact with the second spin polarization layer and the second spin kill layer.

### Claim 3 (depends on 2)

The magnetic recording head of claim 2, wherein the first spin kill layer is disposed over a hot seed layer or a hot seed notch, wherein the hot seed layer is disposed on the shield, and wherein the hot seed notch is disposed on the hot seed layer.

### Claim 4 (depends on 2)

The magnetic recording head of claim 2, wherein the spintronic device further comprises a third negative beta material layer disposed between and in contact with the first spin kill layer and a hot seed layer or a hot seed notch.

### Claim 5 (depends on 4)

The magnetic recording head of claim 4, wherein the spintronic device further comprises a fourth negative beta material layer disposed between the first spin kill layer and the first spin polarization layer.

### Claim 6 (depends on 5)

The magnetic recording head of claim 5, wherein the first, second, third, and fourth negative beta material layers each individually comprises FeCr and has a thickness of about 1 nm.

### Claim 7 (depends on 1)

The magnetic recording head of claim 1, wherein the spintronic device further comprises:
a first spacer layer disposed between and in contact with the first spin polarization layer and the first field generation layer;
a second spacer layer disposed between and in contact with the first field generation layer and the second spin polarization layer; and
a third spacer layer disposed between the second field generation layer and the main pole.

### Claim 8 (depends on 1)

The magnetic recording head of claim 1, wherein the first and second spin kill layers each comprises a non-magnetic material having a resistivity greater than about 100 nano-Ohm·m.

### Claim 9 (depends on 8)

The magnetic recording head of claim 8, wherein the non-magnetic material is Cr.

### Claim 10 (depends on 1)

A magnetic recording device comprising the magnetic recording head of claim 1, the magnetic recording device configured to flow a current from the shield through the spintronic device to the main pole.

### Claim 11

A magnetic recording device, comprising:
a magnetic recording head, the magnetic recording head comprising:
a main pole;
a shield; and
a spintronic device disposed between the main pole and the shield, the spintronic device comprising:
a first spin kill layer;
a first spin polarization layer;
a first field generation layer;
a second spin polarization layer;
a second spin kill layer;
a second field generation layer; and
one or more negative beta material layers comprising FeCr, wherein the one or more negative beta material layers are disposed in contact with either the first spin kill layer or the second spin kill layer; and
means for flowing a current from the main pole through the spintronic device to the shield.

### Claim 12 (depends on 11)

The magnetic recording device of claim 11, wherein the spintronic device further comprises one or more spacer layers, the one or more spacer layers being disposed in contact with either the first field generation layer or the second field generation layer.

### Claim 13 (depends on 11)

The magnetic recording device of claim 11, wherein the one or more negative beta material layers each has a thickness of about 1 nm, and wherein the first spin kill layer and the second spin kill layer each individually comprises a non-magnetic material having a resistivity greater than about 100 nano-Ohm·m.

### Claim 14 (depends on 11)

The magnetic recording device of claim 11, wherein the first spin kill layer is disposed over the main pole, the first spin polarization layer is disposed over the first spin kill layer, the first field generation layer is disposed over the first spin polarization layer, the second spin polarization layer is disposed over the first field generation layer, the second spin kill layer is disposed over the second spin polarization layer, the second field generation layer is disposed between the second spin kill layer and the shield, and the one or more negative beta material layers are disposed between the main pole and the second field generation layer.

### Claim 15 (depends on 11)

The magnetic recording device of claim 11, wherein the one or more negative beta material layers are disposed between the shield and the second spin polarization layer.

### Claim 16 (depends on 11)

The magnetic recording device of claim 11, wherein the one or more negative beta material layers are spaced from the second field generation layer.

### Claim 17 (depends on 11)

The magnetic recording device of claim 11, wherein the second field generation layer is disposed over the main pole, the second spin kill layer is disposed over the second field generation layer, the second spin polarization layer is disposed over the second spin kill layer, the first field generation layer is disposed over the second spin polarization layer, the first spin polarization layer is disposed over the first field generation layer, the first spin kill layer is disposed over the first spin polarization layer, and the shield is disposed over the first spin kill layer.