IP Library › Granted Patent US 10,026,892
Granted Patent B2
US 10,026,892 · App. 15/794,871 · Granted Jul 17, 2018

Precessional spin current structure for MRAM

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Quick Facts
Patent No.
US 10,026,892
App. No.
15/794,871
Granted
Jul 17, 2018
Kind
B2
Abstract

A magnetoresistive random-access memory (MRAM) is disclosed. MRAM device has a magnetic tunnel junction stack having a significantly improved performance of the free layer in the magnetic tunnel junction structure. The MRAM device utilizes a precessional spin current (PSC) magnetic layer in conjunction with a perpendicular MTJ where the in-plane magnetization direction of the PSC magnetic layer is free to rotate.

Claims (28)

1. A magnetic device, comprising:

a precessional spin current magnetic layer in a first plane, the precessional spin current magnetic layer having a magnetization vector with a magnetization component in the first plane which freely rotates in any magnetic direction:

a non-magnetic spacer layer in a second plane and disposed over the precessional spin current magnetic layer;

a free magnetic layer in a third plane and disposed over the non-magnetic spacer layer, the free magnetic layer having a magnetization vector that is perpendicular to the third plane and having a magnetization direction that precesses from a first magnetization direction to a second magnetization direction when a spin-polarized current passes there through, wherein the precessional spin current magnetic layer is electronically coupled to the free magnetic layer;

a non-magnetic tunnel barrier layer in a fourth plane and disposed over the free magnetic layer;

a synthetic antiferromagnetic structure in a fifth plane, the synthetic antiferromagnetic structure including a magnetic reference layer, the magnetic reference layer having a magnetization vector that is perpendicular to the fifth plane and having a fixed magnetization direction, the magnetic reference layer, the non-magnetic tunnel barrier and the free magnetic layer forming a magnetic tunnel junction; and

wherein the magnetization vector with the magnetization component in the first plane of the precessional spin current magnetic layer follows precession of the magnetization direction of the free magnetic layer, rotation of the magnetization component in the first plane of the precessional spin current magnetic layer causing spin polarization of electrons of electrical current passing there through to change in a manner corresponding to the magnetic vector of the precessional spin current magnetic layer, thereby creating the spin-polarized current, the spin-polarized current thereby causing spin transfer torque to assist switching of the magnetization vector of the free magnetic layer, the free magnetic layer storing a memory value.

2. The magnetic device of claim 1 wherein the precessional spin current magnetic layer has a circular shape.

3. The magnetic device of claim 1 wherein the magnetization direction of the magnetization vector of the precessional spin current magnetic layer is in the first plane.

4. The magnetic device of claim 1 wherein the magnetization direction of the precessional spin current magnetic layer has a magnetization component in the first plane that freely rotates in the first plane.

5. The magnetic device of claim 1 wherein the precessional spin current magnetic layer comprises CoFeB.

6. The magnetic device of claim 1 wherein the precessional spin current magnetic layer is magnetically coupled to the free magnetic layer.

7. The magnetic device of claim 1 wherein precession of the precessional spin current magnetic layer is synchronized to precession of the free magnetic layer.

8. The magnetic device of claim 1 wherein the precessional spin current magnetic layer has a rotation frequency greater than zero.

9. A magnetic device, comprising:

a precessional spin current magnetic layer in a first plane, the precessional spin current magnetic layer having a magnetization vector with a magnetization component in the first plane which freely rotates in any magnetic direction:

a non-magnetic spacer layer in a second plane and disposed over the precessional spin current magnetic layer;

a free magnetic layer in a third plane and disposed over the non-magnetic spacer layer, the free magnetic layer having a magnetization vector that is perpendicular to the third plane and having a magnetization direction that precesses from a first magnetization direction to a second magnetization direction when a spin-polarized current passes there through, wherein the precessional spin current magnetic layer is electronically coupled to the free magnetic layer;

a non-magnetic tunnel barrier layer in a fourth plane and disposed over the free magnetic layer;

a magnetic reference layer in a fifth plane, the magnetic reference layer having a magnetization vector that is perpendicular to the fifth plane and having a fixed magnetization direction, the magnetic reference layer, the non-magnetic tunnel barrier and the free magnetic layer forming a magnetic tunnel junction;

wherein the magnetization vector with the magnetization component in the first plane of the precessional spin current magnetic layer follows precession of the magnetization direction of the free magnetic layer, rotation of the magnetization component in the first plane of the precessional spin current magnetic layer causing spin polarization of electrons of electrical current passing there through to change in a manner corresponding to the magnetic vector of the precessional spin current magnetic layer, thereby creating the spin-polarized current, the spin-polarized current thereby causing spin transfer torque to assist switching of the magnetization vector of the free magnetic layer, the free magnetic layer storing a memory value.

10. The magnetic device of claim 9 wherein the precessional spin current magnetic layer has a circular shape.

11. The magnetic device of claim 9 wherein the magnetization direction of the magnetization vector of the precessional spin current magnetic layer is in the first plane.

12. The magnetic device of claim 9 wherein the magnetization direction of the precessional spin current magnetic layer has a magnetization component in the first plane that freely rotates in the first plane.

13. The magnetic device of claim 9 wherein the precessional spin current magnetic layer comprises CoFeB.

14. The magnetic device of claim 9 wherein the precessional spin current magnetic layer is magnetically coupled to the free magnetic layer.

15. The magnetic device of claim 9 wherein precession of the precessional spin current magnetic layer is synchronized to precession of the free magnetic layer.

16. The magnetic device of claim 9 wherein the precessional spin current magnetic layer has a rotation frequency greater than zero.

Assignments (4)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 11, 2021
From: SPIN (ASSIGNMENT FOR BENEFIT OF CREDITORS), LLC
To: INTEGRATED SILICON SOLUTION, (CAYMAN) INC.
Reel/Frame 057473/0319 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 20, 2021
From: SPIN MEMORY, INC.
To: SPIN (ASSIGNMENT FOR THE BENEFIT OF CREDITORS), LLC
Reel/Frame 056927/0038 →
CHANGE OF NAME Recorded Jan 15, 2019
From: SPIN TRANSFER TECHNOLOGIES, INC.
To: SPIN MEMORY, INC.
Reel/Frame 048075/0550 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 26, 2017
From: PINARBASI, MUSTAFA MICHAEL; TZOUFRAS, MICHAIL; KARDASZ, BARTLOMIEJ ADAM
To: SPIN TRANSFER TECHNOLOGIES, INC.
Reel/Frame 043962/0133 →