Reader noise reduction using spin hall effects

Patent metadata

Field	Value
Publication number	US-11205447-B2
Application number	US-201916546397-A
Country	US
Kind code	B2
Filing date	Aug 21, 2019
Priority date	Aug 21, 2019
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

Abstract

A read head is disclosed wherein a Spin Hall Effect (SHE) layer is formed on a free layer (FL) in a sensor and between the FL and top shield (S 2 ). Preferably, the sensor has a seed layer, an AP2 reference layer, antiferromagnetic coupling layer, AP1 reference layer, and a tunnel barrier sequentially formed on a bottom shield (S 1 ). In a three terminal configuration, a first current flows between S 1 and S 2 such that the AP1 reference layer produces a first spin torque on the FL, and a second current flows across the SHE layer thereby generating a second spin torque on the FL that opposes the first spin torque. When the stripe heights of the FL and SHE layer are equal, a two terminal configuration is employed where a current flows between one side of the SHE layer to a center portion thereof and then to S 1 , or vice versa.

First claim

We claim:

1. A read head, comprising:
(a) a bottom shield (S 1 ) having a front side at an air bearing surface (ABS), and a top surface;
(b) a top shield (S 2 ) having a front side at the ABS, and a bottom surface;
(c) a magnetoresistive (MR) sensor formed on S 1 at the ABS, comprising:
(1) a free layer (FL) with a magnetization in a first cross-track (longitudinal) direction, a front side at the ABS, and a back side at a first stripe height (SH 1 ) from the ABS;
(2) an AP1 reference layer with a magnetization that is orthogonal to the ABS in a first transverse direction, and wherein the AP1 reference layer is antiferromagnetically (AF) coupled to an AP2 reference layer through an AF coupling layer; and
(3) a non-magnetic layer between the FL and AP1 reference layer; and

(d) a Spin Hall Effect (SHE) layer comprised of a positive Spin Hall Angle (SHA) material and formed on the FL and with a second stripe height (SH 2 ) between a front side and backside thereof, and wherein a top surface of the SHE layer is separated from the S 2 bottom surface by an insulation layer, and wherein the SHE layer is configured to spin polarize a current and generate a first spin torque on the FL that opposes a second spin torque generated by the AP1 reference layer on the FL when the current flows from a first side of the SHE layer to a second side of the SHE layer in the first cross-track direction when a portion of the current flows through the MR sensor from the SHE layer to the S 1 , or the current flows from the second side of the SHE layer to the first side of the SHE layer in a direction opposite to the first cross-track direction when the portion of current through the MR sensor flows from the S 1 to the SHE layer thereby reducing spin torque induced magnetic noise in the FL.

2. The read head of claim 1 wherein the SHE layer has a down-track thickness less than 12 nm.

3. The read head of claim 1 wherein the SHE layer has an absolute value for SHA that is >0.05.

4. The read head of claim 1 wherein the SHE layer front side is at the ABS.

5. The read head of claim 4 wherein the SHE layer backside is formed between the ABS and a bottom portion of S 2 that has a front side at height h 2 from the ABS where h 2 >SH 2 .

6. The read head of claim 1 wherein the SHE layer front side is recessed behind a bottom portion of S 2 .

7. The read head of claim 1 wherein the non-magnetic layer is a tunnel barrier layer.

8. The read head of claim 1 wherein the MR sensor is further comprised of an antiferromagnetic (AFM) layer that is formed behind an upper portion of S 1 , and wherein the AFM layer pins a magnetization in the AP2 reference layer.

9. The read head of claim 1 wherein SH 2 is greater than SH 1 .

10. A head gimbal assembly (HGA), comprising:
(a) the read head of claim 1 ; and
(b) a suspension that elastically supports the read head, wherein the suspension has a flexure to which the read head is joined, a load beam with one end connected to the flexure, and a base plate connected to the other end of the load beam.

11. A magnetic recording apparatus, comprising:
(a) the HGA of claim 10 ;
(b) a magnetic recording medium positioned opposite to a slider on which the read head is formed;
(c) a spindle motor that rotates and drives the magnetic recording medium; and
(d) a device that supports the slider, and that positions the slider relative to the magnetic recording medium.

Assignees

• Headway Tech Inc

Inventors

• Chen Wenyu
• Wu Yan

Classifications

• G11B5/3932

  Magnetic biasing films · CPC title

• G11B5/3909 Primary

  Arrangements using a magnetic tunnel junction · CPC title

• G11B5/37

  using galvano-magnetic devices, e.g. Hall-effect devices (G11B5/39 takes precedence){using Hall or Hall-related effect, e.g. planar-Hall effect or pseudo-Hall effect} · CPC title

• G11B5/3945

  Heads comprising more than one sensitive element · CPC title

• G11B5/398

  Specially shaped layers · CPC title