Magnetoresistive element and magnetic memory

• US 10,651,369 B2
• Filed: 12/28/2016
• Issued: 05/12/2020
• Est. Priority Date: 06/04/2010
• Status: Active Grant

• Current Assignee: Tohoku University National Universities Corporation
• Original Assignee: Tohoku University National Universities Corporation
• Inventors: Ohno, Hideo, Ikeda, Shoji, Matsukura, Fumihiro, Endoh, Masaki, Kanai, Shun, Yamamoto, Hiroyuki, Miura, Katsuya
• Primary Examiner(s): Bernatz, Kevin M
• Application Number:
  US15/392,556
• Publication Number:
  US 20170110654A1
• Time in Patent Office: 1,231 Days
• Field of Search: None
• CPC Class Codes: G01R 33/098 comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
• CPC Class Codes: G11B 5/31 using thin films G11B5/1274, G11B5/1278, G11B5/1874, G11B5/1875, G11B5/33, G11B5/49 take precedence; magnetic thin film structures H01F10/00
• CPC Class Codes: G11C 11/16 using elements in which the storage effect is based on magnetic spin effect
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/80 Constructional details
• CPC Class Codes: H10N 50/85 Magnetic active materials
• CPC Class Codes: Y10T 428/1114 having tunnel junction effect

Abstract

Provided are a magneto resistive effect element with a stable magnetization direction perpendicular to a film plane and with a controlled magnetoresistance ratio, and a magnetic memory using the magneto resistive effect element. Ferromagnetic layers of the magneto resistive effect element are formed from a ferromagnetic material containing at least one type of 3d transition metal such that the magnetoresistance ratio is controlled, and the film thickness of the ferromagnetic layers is controlled on an atomic layer level such that the magnetization direction is changed from a direction in the film plane to a direction perpendicular to the film plane.

Claims

1. A magnetoresistive element, comprising:

a reference layer having a fixed magnetization direction and including a ferromagnetic material;

a recording layer having a variable magnetization direction and including a ferromagnetic material; and

a non-magnetic layer that is electrically connected between the reference layer and the recording layer and that contains oxygen, the non-magnetic layer being a tunnel coupling layer through which a tunnel current flows, wherein

the reference layer, the recording layer and the tunnel coupling layer are arranged so that a magnetization direction of the one of the reference layer and the recording layer becomes perpendicular to a layer surface by an interfacial perpendicular magnetic anisotropy at an interface between the tunnel coupling layer and the one of the reference layer and the recording layer, resulting from the one of the reference layer and the recording layer having a predetermined thickness,

when the one of the reference layer and the recording layer is the recording layer, the recording layer contains Co or Fe, and has a bcc structure, the magnetoresistive element further comprising a non-magnetic capping layer formed directly on one surface of the recording layer opposite to an other surface of the recording layer on which the tunnel coupling layer is directly formed so that the recording layer is sandwiched by the tunnel coupling layer and the non-magnetic capping layer, the predetermined thickness of the recording layer being equal to or less than 3 nm, and

when the one of the reference layer and the recording layer is the reference layer, the reference layer contains Co or Fe, and has a bcc structure, the magnetoresistive element further comprising an non-magnetic underlayer formed directly on one surface of the reference layer opposite to an other surface of the reference layer on which the tunnel coupling layer is directly formed so that the reference layer is sandwiched by the tunnel coupling layer and the non-magnetic underlayer, the predetermined thickness of the reference layer being equal to or less than 3 nm.

2. The magnetoresistive element according to claim 1, wherein the predetermined thickness of the one of the reference layer and the recording layer is in a range of 1.0 nm to 1.6 nm.

3. The magnetoresistive element according to claim 1, wherein the one of the reference layer and the recording layer further includes B.

4. The magnetoresistive element according to claim 1, wherein the tunnel coupling layer contains Mg.

5. The magnetoresistive element according to claim 1, wherein the one of the reference layer and the recording layer has a laminate structure including a plurality of alternating ferromagnetic and non-magnetic laminated layers, and

in order from a surface in contact with the tunnel coupling layer, one of an uppermost layers of the reference layer and an lowermost layers of the recording layer in the laminated structure is ferromagnetic laminated layer.

6. The magnetoresistive element according to claim 1, wherein when the one of the reference layer and the recording layer is the recording layer, the magnetoresistive element further comprising an other non-magnetic layer formed directly on one surface of the reference layer opposite to an other surface of the reference layer on which the tunnel coupling layer is directly formed so that the reference layer is sandwiched by the tunnel coupling layer and the other non-magnetic layer.

7. A magnetoresistive element, comprising:

a reference layer having a fixed magnetization direction and including a ferromagnetic material;

a recording layer having a variable magnetization direction and including a ferromagnetic material; and

a non-magnetic layer that is electrically connected between the reference layer and the recording layer and that contains oxygen, the non-magnetic layer being a tunnel coupling layer through which a tunnel current flows, wherein

the reference layer, the recording layer and the tunnel coupling layer are arranged so that a magnetization direction of the one of the reference layer and the recording layer becomes perpendicular to a layer surface by an interfacial perpendicular magnetic anisotropy at an interface between the tunnel coupling layer and the one of the reference layer and the recording layer, resulting from the one of the reference layer and the recording layer having a predetermined thickness,

when the one of the reference layer and the recording layer is the recording layer, the recording layer contains CoFeB, and has a bcc structure, the predetermined thickness of the recording layer being equal to or less than 3 nm, and

when the one of the reference layer and the recording layer is the reference layer, the reference layer contains CoFeB, and has a bcc structure, the predetermined thickness of the reference layer being equal to or less than 3 nm.

8. The magnetoresistive element according to claim 7, wherein the predetermined thickness of the one of the reference layer and the recording layer is in a range of 1.0 nm to 1.6 nm.

9. The magnetoresistive element according to claim 7, wherein the one of the reference layer and the recording layer further includes B.

10. The magnetoresistive element according to claim 7, wherein the tunnel coupling layer contains Mg.

11. A magnetoresistive element, comprising:

a reference layer having a fixed magnetization direction and including a ferromagnetic material;

a recording layer having a variable magnetization direction and including a ferromagnetic material; and

a non-magnetic layer that is electrically connected between the reference layer and the recording layer and that contains oxygen, the non-magnetic layer being a tunnel coupling layer through which a tunnel current flows, wherein

the reference layer, the recording layer and the tunnel coupling layer are arranged so that a magnetization direction of the one of the reference layer and the recording layer becomes perpendicular to a layer surface by an interfacial perpendicular magnetic anisotropy at an interface between the tunnel coupling layer and the one of the reference layer and the recording layer, resulting from the one of the reference layer and the recording layer having a predetermined thickness,

when the one of the reference layer and the recording layer is the recording layer, the recording layer contains Co or Fe, and has a bcc structure, the magnetoresistive element further comprising a first non-magnetic layer formed directly on one surface of the recording layer opposite to an other surface of the recording layer on which the tunnel coupling layer is directly formed so that the recording layer is sandwiched by the tunnel coupling layer and the first non-magnetic layer, the first non-magnetic layer containing Ta, Cu or Mg, the predetermined thickness of the recording layer being equal to or less than 3 nm, and

when the one of the reference layer and the recording layer is the reference layer, the reference layer contains Co or Fe, and has a bcc structure, the magnetoresistive element further comprising a second non-magnetic layer formed directly on one surface of the reference layer opposite to an other surface of the reference layer on which the tunnel coupling layer is directly formed so that the reference layer is sandwiched by the tunnel coupling layer and the second non-magnetic layer, the second non-magnetic layer containing Ta or Mg, the predetermined thickness of the reference layer being equal to or less than 3 nm.

12. The magnetoresistive element according to claim 11, wherein the predetermined thickness of the one of the reference layer and the recording layer is in a range of 1.0 nm to 1.6 nm.

13. The magnetoresistive element according to claim 11, wherein the one of the reference layer and the recording layer further includes B.

14. The magnetoresistive element according to claim 11, wherein the tunnel coupling layer contains Mg.