Topological Insulator Based Spin Torque Oscillator Reader

Patent metadata

Field	Value
Publication number	US-2023419990-A1
Application number	US-202318244555-A
Country	US
Kind code	A1
Filing date	Sep 11, 2023
Priority date	May 31, 2022
Publication date	Dec 28, 2023
Grant date	—

Abstract

The present disclosure generally relates to a bismuth antimony (BiSb) based STO (spin torque oscillator) sensor. The STO sensor comprises a SOT device and a magnetic tunnel junction (MTJ) structure. By utilizing a BiSb layer within the SOT device, a larger spin Hall angle (SHA) can be achieved, thereby improving the efficiency and reliability of the STO sensor.

First claim

What is claimed is:

1 . A sensor, comprising:
a seed layer; a magnetic tunnel junction (MTJ) structure disposed over the seed layer; a first buffer layer disposed over the MTJ structure; a bismuth antimony (BiSb) layer disposed over the first buffer layer; a second buffer layer disposed over the BiSb layer; a capping layer disposed over the second buffer layer, wherein the seed layer, the MTJ structure, the first buffer layer, the BiSb layer, the second buffer layer, and the capping layer are disposed at a media facing surface (MFS); and an antiferromagnetic (AFM) layer, wherein the AFM is adjacent to the MTJ structure.

2 . The sensor of claim 1 , wherein the AFM layer is disposed at the MFS and in contact with the seed layer.

3 . The sensor of claim 1 , wherein the AFM layer and a free layer of the MTJ structure are at least partially aligned in a direction perpendicular to the MFS.

4 . The sensor of claim 1 , wherein the AFM layer and a free layer of the MTJ structure are not aligned in a direction perpendicular to the MFS.

5 . The sensor of claim 1 , wherein the first buffer layer is disposed in contact with a free layer of the MTJ structure.

6 . A magnetic recording head comprising the sensor of claim 1 .

7 . A magnetic recording device, comprising:
a magnetic recording media; the magnetic recording head of claim 6 ; and a control unit configured to:
flow current through the bismuth antimony (BiSb) layer while reading data from the magnetic recording media; and
measure frequency of a precession of a free layer in the sensor, wherein the precession is responsive to a magnetic field generated by the magnetic recording media.

8 . A sensor, comprising:
a seed layer; a magnetic tunnel junction (MTJ) structure disposed over the seed layer, the MTJ structure comprising:
a pinning layer disposed on the seed layer;
an insulation layer disposed on the seed layer; and
a free layer disposed on the insulation layer;
a first buffer layer disposed over the MTJ structure; a bismuth antimony (BiSb) layer disposed over the first buffer layer; a second buffer layer disposed over the BiSb layer; a capping layer disposed over the second buffer layer, wherein the seed layer, the MTJ structure, the first buffer layer, the BiSb layer, the second buffer layer, and the capping layer are disposed at a media facing surface (MFS); and an antiferromagnetic (AFM) layer, wherein the AFM is adjacent to the MTJ structure and in contact with the seed layer.

9 . The sensor of claim 8 , wherein the AFM layer is disposed at the MFS.

10 . The sensor of claim 8 , wherein the AFM layer is recessed from the MFS.

11 . The sensor of claim 8 , wherein the AFM layer and the free layer are at least partially aligned in a direction perpendicular to the MFS.

12 . The sensor of claim 8 , wherein the AFM layer and the free layer are unaligned in a direction perpendicular to the MFS.

13 . A magnetic recording head comprising the sensor of claim 8 .

14 . A method of using a magnetic recording head, comprising:
flowing a current through a spin orbit torque (SOT) device of a spin torque oscillator (STO) sensor while reading data from a magnetic recording media; and measuring frequency of a precession of a free layer in the STO sensor, wherein the precession is responsive to a magnetic field generated by the magnetic recording media.

15 . The method of claim 14 , wherein the SOT device has a spin Hall angle of 2 or more.

16 . The method of claim 14 , wherein the SOT device is disposed in a read head of the magnetic recording head.

17 . The method of claim 14 , wherein the current is flowed in-plane inside a BiSb layer of the SOT device.

18 . The method of claim 17 , further comprising flowing a small sensing current perpendicular to a plane of the magnetic recording media, wherein a signal is read out by the measuring.

19 . The method of claim 14 , wherein there is a linear relationship between the measured frequency and an applied magnetic field.

20 . The method of claim 14 , further comprising detecting a bit recorded on the magnetic recording media based upon the measured frequency.

Assignees

• Western Digital Tech Inc

Inventors

• Liu Xiaoyong
• Li Zhanjie
• Le Quang
• York Brian R
• Hwang Cherngye
• Ho Kuok San
• Takano Hisashi

Classifications

• G11B5/3967

  Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read (G11B5/3906 takes precedence) · CPC title

• G11B5/3909 Primary

  Arrangements using a magnetic tunnel junction · CPC title

• G11B5/3912 Primary

  Arrangements in which the active read-out elements are transducing in association with active magnetic shields, e.g. magnetically coupled shields (G11B5/3916 takes precedence) · CPC title

• G11B5/11

  Shielding of head against electric or magnetic fields · CPC title

• G11B5/3932

  Magnetic biasing films · CPC title