Data reader with resonant tunneling

Patent metadata

Field	Value
Publication number	US-2016254012-A1
Application number	US-201514633898-A
Country	US
Kind code	A1
Filing date	Feb 27, 2015
Priority date	Feb 27, 2015
Publication date	Sep 1, 2016
Grant date	—

Abstract

A data reader may have an resonant tunnel structure disposed between first and second magnetic structures. The resonant tunnel structure can be configured with a spacer layer disposed between first and second barrier layers. The first barrier layer can have a first thickness that is smaller than a second thickness of the second barrier layers with the thicknesses each measured along a common plane to provide resonant tunneling for the data reader.

First claim

1 . An apparatus comprising a data reader having a resonant tunnel structure disposed between first and second magnetic structures, the resonant tunnel structure comprising a spacer layer disposed between first and second barrier layers having different thicknesses measured along a common plane.

2 . The apparatus of claim 1 , wherein the first barrier layer has a first thickness and the second barrier layer has a second thickness, the first thickness being smaller than the second thickness.

3 . The apparatus of claim 2 , wherein the first thickness is 1 nm, the second thickness is less than 2 nm, and a third thickness of the spacer layer is 1.3 nm along the common plane.

4 . The apparatus of claim 1 , wherein the spacer layer is a metallic material.

5 . The apparatus of claim 1 , wherein the spacer layer is a non-magnetic material.

6 . The apparatus of claim 1 , wherein the first magnetic structure is fixed to a magnetic orientation by a pinning layer.

7 . The apparatus of claim 1 , wherein the different thicknesses of the first and second barrier layers correspond to bias-dependent resonant tunneling between the first and second magnetic structures.

8 . The apparatus of claim 1 , wherein the first and second barrier layers each comprise MgO and the spacer layer comprises a transition metal material.

9 . The apparatus of claim 1 , wherein the common plane is parallel to an air bearing surface (ABS).

10 . The apparatus of claim 1 , wherein the second magnetic structure is magnetically free and sensitive to an external magnetization.

11 . An apparatus comprising:
a data reader a data reader having a resonant tunnel structure disposed between first and second magnetic structures, the resonant tunnel structure comprising a first barrier layer having a first thickness, a second barrier layer having a second thickness, and a spacer layer having a third thickness, the spacer layer disposed between first and second barrier layers, the first, second, and third thicknesses being different and each measured along a common plane; a data storage medium separated from the data reader by an air bearing; and a data bit stored in the data storage medium.

12 . The apparatus of claim 11 , wherein the third thickness is less than the second thickness and greater than the first thickness.

13 . The apparatus of claim 11 , wherein the first barrier layer contacts the first magnetic structure, the first magnetic structure having a fixed magnetization.

14 . The apparatus of claim 11 , wherein the second barrier layer contacts the second magnetic structure, the second magnetic structure is magnetically free and sensitive to the data bit.

15 . The apparatus of claim 11 , wherein the data reader is disposed between first and second magnetic shields.

16 . The apparatus of claim 11 , wherein the spacer layer has a first magnetization direction oriented orthogonally to a second magnetization direction of the first magnetic structure.

17 . The apparatus of claim 11 , wherein the spacer layer is magnetically free and sensitive to the data bit.

18 . A method comprising:
disposing an resonant tunnel structure of a data reader between first and second magnetic structures, the resonant tunnel structure comprising a spacer layer disposed between first and second barrier layers having different thicknesses measured along a common plane; and passing a current through the data reader to sense a data bit stored on an adjacent data storage medium.

19 . The method of claim 18 , wherein the different thicknesses of the first and second barrier layers produce bias-dependent resonant tunneling through the resonant tunnel structure.

20 . The method of claim 19 , wherein the bias-dependent resonant tunneling has a transmission coefficient of 1 at a bias voltage applied between the first and second magnetic structures.

Assignees

• Seagate Technology Llc

Inventors

• Deen David A
• Dunn Thomas E

Classifications

• G11B5/398 Primary

  Specially shaped layers · CPC title

• G11B5/3909 Primary

  Arrangements using a magnetic tunnel junction · CPC title