MAGNETIC DEVICES AND STRUCTURES

• US 20120241885A1
• Filed: 06/06/2012
• Published: 09/27/2012
• Est. Priority Date: 09/03/2009
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hu, Guohan, Sun, Jonathan Zanghong
• Granted Patent: US 8,717,808 B2
• Time in Patent Office: Days
• US Class Current: 257/421
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell

Abstract

Magnetic devices, magnetoresistive structures, and methods and techniques associated with the magnetic devices and magnetoresistive structures are presented. For example, a magnetic device is presented. The magnetic device includes a ferromagnet, an antiferromagnet coupled to the ferromagnet, and a nonmagnetic metal proximate to the ferromagnet. The antiferromagnet provides uniaxial anisotropy to the magnetic device. A resistance of the nonmagnetic metal is dependent upon a direction of a magnetic moment of the ferromagnet.

Claims

1. A magnetic device comprising:

a free ferromagnet layer;

an antiferromagnet layer coupled to the free ferromagnet layer; and

a nonmagnetic metal proximate to the free ferromagnet layer;

wherein the antiferromagnet layer provides uniaxial anisotropy to the free ferromagnet layer, wherein exchange coupling energy of an exchange coupling between the antiferromagnet layer and the free ferromagnet layer is greater than energy associated with the uniaxial anisotropy; and

wherein a resistance of the nonmagnetic metal is dependent upon a direction of a magnetic moment of the free ferromagnet layer.

2. The magnetic device of claim 1, wherein the antiferromagnet layer provides volume anisotropy that provides a thermal activation barrier for the magnetic device.

3. The magnetic device of claim 1, wherein the free ferromagnet layer is a nanoferromagnet.

4. A magnetoresistive memory device comprising:

a free ferromagnetic layer;

an antiferromagnetic layer coupled to the free ferromagnetic layer, wherein a free side of the magnetoresistive structure comprises the free ferromagnetic layer and the antiferromagnetic layer;

a pinned layer; and

a nonmagnetic metallic layer at least partly between the free side and the pinned layer;

wherein the antiferromagnetic layer provides uniaxial anisotropy to the free ferromagnetic layer of the free side;

wherein a resistance of the nonmagnetic metallic layer is dependent upon a direction of a magnetic moment of the free ferromagnetic layer; and

wherein the magnetoresistive memory device stores at least two data states corresponding to at least two directions of the magnetic moment of the free ferromagnetic layer.

5. An integrated circuit comprising:

a free ferromagnetic layer;

an antiferromagnetic layer coupled to the free ferromagnetic layer, wherein a free side of the magnetoresistive structure comprises the free ferromagnetic layer and the antiferromagnetic layer;

a pinned layer;

a nonmagnetic metallic layer at least partly between the free side and the pinned layer; and

a substrate on which the pinned layer, the nonmagnetic metallic layer, the free ferromagnetic layer and the ferrimagnetic layer are formed;

wherein the antiferromagnetic layer provides uniaxial anisotropy to the free ferromagnetic layer of the free side, wherein exchange coupling energy of an exchange coupling between the antiferromagnet layer and the free ferromagnet layer is greater than energy associated with the uniaxial anisotropy; and

wherein a resistance of the nonmagnetic metallic layer is dependent upon a direction of a magnetic moment of the free ferromagnetic layer.

6. A method for forming a magnetoresistive structure, the method comprising the steps of:

forming a free ferromagnetic layer;

forming an antiferromagnetic layer coupled to the free ferromagnetic layer, wherein a free side of the magnetoresistive structure comprises the free ferromagnetic layer and the antiferromagnetic layer;

forming a pinned layer; and

forming a nonmagnetic metallic layer at least partly between the free side and the pinned layer;

wherein the antiferromagnetic layer provides uniaxial anisotropy to the free ferromagnetic layer of the free side, wherein exchange coupling energy of an exchange coupling between the antiferromagnet layer and the free ferromagnet layer is greater than energy associated with the uniaxial anisotropy; and

wherein a resistance of the nonmagnetic metallic layer is dependent upon a direction of a magnetic moment of the free ferromagnetic layer.