INVERTED ORTHOGONAL SPIN TRANSFER LAYER STACK

• US 20140103472A1
• Filed: 10/14/2013
• Published: 04/17/2014
• Est. Priority Date: 10/17/2012
• Status: Active Grant

• Current Assignee: New York University
• Original Assignee: New York University
• Inventors: KENT, Andrew, BACKES, Dirk
• Granted Patent: US 9,082,888 B2
• Time in Patent Office: Days
• US Class Current: 257/421
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• 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: H01F 10/3272 by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
• CPC Class Codes: H01F 41/307 insulating or semiconductive spacer
• CPC Class Codes: H10N 15/00 Thermoelectric devices without a junction of dissimilar materials; Thermomagnetic devices, e.g. using the Nernst-Ettingshausen effect integrated devices or assemblies of multiple devices H10N19/00
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A magnetic device includes a pinned magnetic layer having a first fixed magnetization vector with a first fixed magnetization direction. The magnetic device also includes a free magnetic layer having a variable magnetization vector having at least a first stable state and a second stable state. The magnetic device also has a first non-magnetic layer and a reference. The first non-magnetic layer spatially separates the pinned magnetic layer and the free magnetic layer. The magnetic device also includes a second non-magnetic layer spatially separating the free magnetic layer and the reference magnetic layer. A magnetic tunnel junction, located below the pinned magnetic layer, is formed by the free magnetic layer, the second non-magnetic layer, and the reference magnetic layer. Application of a current pulse, having either positive or negative polarity and a selected amplitude and duration, through the magnetic device switches the variable magnetization vector.

Claims

1. A magnetic device comprising:

a pinned magnetic layer having a first fixed magnetization vector with a first fixed magnetization direction;

a free magnetic layer having a variable magnetization vector having at least a first stable state and a second stable state;

a first non-magnetic layer spatially separating the pinned magnetic layer and the free magnetic layer;

a reference magnetic layer having a second fixed magnetization vector with a second fixed magnetization direction; and

a second non-magnetic layer spatially separating the free magnetic layer and the reference magnetic layer, wherein a magnetic tunnel junction is formed by the free magnetic layer, the second non-magnetic layer, and the reference magnetic layer, wherein application of a current pulse, having a selected amplitude and duration, through the magnetic device switches the variable magnetization vector, and wherein the magnetic tunnel junction is spatially located below the pinned magnetic layer.

2. The magnetic device of claim 1, wherein the first fixed magnetization vector is perpendicular to a plane of the pinned magnetic layer.

3. The magnetic device of claim 1, further comprising a synthetic antiferromagnet layer comprising the pinned magnetic layer.

4. The magnetic device of claim 3, wherein the synthetic antiferromagnet layer reduces magnetic interactions between the pinned magnetic layer and the free magnetic layer.

5. The magnetic device of claim 3, wherein the synthetic antiferromagnet layer is a material selected from the group consisting of ruthenium, chromium, or copper.

6. The magnetic device of claim 3, further comprising an antiferromagnet that pins the synthetic antiferromagnet layer providing a perpendicular exchange bias.

7. The magnetic device of claim 6, wherein the antiferromagnet is comprised of iridium manganese.

8. The magnetic device of claim 1, wherein the second non-magnetic insulating layer has an amplitude of roughness less than or equal to 0.8 nanometers.

9. The magnetic device of claim 1, wherein the second non-magnetic insulating layer has a wavelength of roughness less than or equal to 23.2 nanometers.

10. The magnetic device of claim 1, further comprising a second magnetic tunnel junction comprising the pinned magnetic layer and the free magnetic layer.

11. The magnetic device of claim 1, wherein the variable magnetization vector represents a bit of information.

12. A memory system comprising:

a memory cell comprising;

a pinned magnetic layer having a first fixed magnetization vector with a first fixed magnetization direction;

a free magnetic layer having a variable magnetization vector having at least a first stable state and a second stable state;

a first non-magnetic layer spatially separating the pinned magnetic layer and the free magnetic layer;

a reference magnetic layer having a second fixed magnetization vector with a second fixed magnetization direction; and

a second non-magnetic layer spatially separating the free magnetic layer and the reference magnetic layer, wherein a magnetic tunnel junction is formed by the free magnetic layer, the second non-magnetic layer, and the reference magnetic layer, wherein application of a current pulse, having a selected amplitude and duration, through the magnetic device switches the variable magnetization vector, and wherein the magnetic tunnel junction is spatially located below the pinned magnetic layer; and

a current source connected to the pinned magnetic layer and the reference magnetic layer such that current passes from the second non-magnetic layer to the pinned magnetic layer.

13. The memory system of claim 12, wherein the memory cell further comprises a synthetic antiferromagnet layer, wherein the synthetic antiferromagent layer comprises the pinned magnetic layer.

14. The memory system of claim 13, wherein the synthetic antiferromagnet layer reduces magnetic interactions between the pinned magnetic layer and the free magnetic layer.

15. The memory system of claim 13, wherein the synthetic antiferromagnet layer is a material selected from the group consisting of ruthenium, chromium, or copper.

16. The memory system of claim 13, further comprising an antiferromagnet that pins the synthetic antiferromagnet layer providing a perpendicular exchange bias.

17. The memory system of claim 12, further comprising a second magnetic tunnel junction comprising the pinned magnetic layer and the free magnetic layer.

18. A method of making a memory device, comprising:

forming a second non-magnetic layer spatially separating a free magnetic layer and a reference magnetic layer, wherein a magnetic tunnel junction is formed by the free magnetic layer, the second non-magnetic layer, and the reference magnetic layer, wherein application of a current pulse, having either positive or negative polarity and a selected amplitude and duration, through the magnetic device switches a variable magnetization vector of the free magnetic layer, and wherein the magnetic tunnel junction is spatially located below the pinned magnetic layer forming the reference magnetic layer having a second fixed magnetization vector with a second fixed magnetization direction;

forming a first non-magnetic layer spatially separating the pinned magnetic layer and the free magnetic layer;

forming a free magnetic layer having the variable magnetization vector having at least a first stable state and a second stable state; and

forming a pinned magnetic layer having a first fixed magnetization vector with a first fixed magnetization direction.

19. The method of making a memory device of claim 18, further comprising forming a synthetic antiferromagnet layer, wherein the synthetic antiferromagent layer comprises the pinned magnetic layer.

20. The method of making a memory device of claim 19, wherein the synthetic antiferromagnet layer reduces magnetic interactions between the pinned magnetic layer and the free magnetic layer.