Non-collinear antiferromagnets for high density and low power spintronics devices

Patent metadata

Field	Value
Publication number	US-10804459-B2
Application number	US-201816225071-A
Country	US
Kind code	B2
Filing date	Dec 19, 2018
Priority date	Dec 19, 2018
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

Spintronic devices based on metallic antiferromagnets having a non-collinear spin structure are provided. Also provided are methods for operating the devices. The spintronic devices are based on a bilayer structure that includes a spin torque layer of an antiferromagnetic material having a non-collinear triangular spin structure adjoining a layer of ferromagnetic material.

First claim

What is claimed is:

1. A spintronic device comprising:
a ferromagnetic layer comprising a ferromagnetic material having perpendicular magnetization;
a spin-torque layer comprising a metallic antiferromagnetic material having a non-collinear spin structure adjoining the ferromagnetic layer at an interface, the metallic antiferromagnetic material characterized in that it is capable of generating spin currents having non-zero out-of-plane spin polarizations when an in-plane charge current is passed through the spin-torque layer; and
a current source configured to pass an in-plane charge current through the spin torque layer.

2. The device of claim 1 , wherein the metallic antiferromagnetic material having a non-collinear spin structure comprises a nitride having the formula Mn 3 AN, where A is gallium, zinc, copper, or nickel.

3. The device of claim 2 , where A is gallium.

4. A method of modulating the magnetization in a spintronic device comprising:
a ferromagnetic layer comprising a ferromagnetic material having a perpendicular magnetization;
a spin-torque layer comprising a metallic antiferromagnetic material having a non-collinear spin structure in contact with the ferromagnetic layer at an interface; and
a current source configured to pass an in-plane charge current through the spin-torque layer, the method comprising:
passing an in-plane charge current through the spin-torque layer, whereby spin currents having out-of-plane spin polarizations are generated in the spin-torque layer giving rise to a spin torque in the ferromagnetic layer that modulates the magnetization of the ferromagnetic material.

5. The method of claim 4 , wherein the spin torque in the ferromagnetic layer switches the magnetization of the ferromagnetic material.

6. The method of claim 4 , wherein the metallic antiferromagnetic material having a non-collinear spin structure comprises a nitride having the formula Mn 3 AN, where A is gallium, zinc, copper, or nickel.

7. A magnetic tunnel junction device comprising;
a magnetic tunnel junction comprising:
a free magnetic layer comprising a ferromagnetic material having a perpendicular magnetization;
a pinned layer comprising a ferromagnetic material having a fixed direction of magnetization; and
a barrier layer comprising an electrically insulating material separating the ferromagnetic layer from the pinned layer;

a spin torque layer comprising a metallic antiferromagnetic material having a non-collinear spin structure in contact with the free magnetic layer at an interface, the metallic antiferromagnetic material characterized in that it is capable of generating spin currents having non-zero out-of-plane spin polarizations when an in-plane charge current is passed through the spin-torque layer;
a write current source configured to pass an in-plane charge current through the spin torque layer;
a read current source configured to pass a charge current through the magnetic tunnel junction; and
a voltage source configured to apply a bias voltage between the pinned layer and the spin-torque layer.

8. The device of claim 7 , wherein the metallic antiferromagnetic material having a non-collinear spin structure comprises a nitride having the formula Mn 3 AN, where A is gallium, zinc, copper, or nickel.

9. The device of claim 8 , where A is gallium.

10. A method of operating a magnetic tunnel junction device comprising:
a magnetic tunnel junction comprising:
a free magnetic layer comprising a ferromagnetic material having a perpendicular magnetization;
a pinned layer comprising a ferromagnetic material having a fixed direction of magnetization; and
a barrier layer comprising an electrically insulating material separating the ferromagnetic layer from the pinned layer;
a spin torque layer comprising a metallic antiferromagnetic material having a non-collinear spin structure in contact with the free magnetic layer at an interface;
a write current source configured to pass an in-plane charge current through the spin torque layer; and
a read current source configured to pass a charge current through the magnetic tunnel junction, the method comprising:
passing an in-plane write current through the spin torque layer, whereby spin currents having out-of-plane spin polarizations are generated in the spin-torque layer, giving rise to a spin torque in the free magnetic layer that switches the magnetization of the free magnetic layer; and
passing a read current through the magnetic tunnel junction and measuring the resistance of the magnetic tunnel junction.

11. The method of claim 10 , wherein the metallic antiferromagnetic material having a non-collinear spin structure comprises a nitride having the formula Mn 3 AN, where A is gallium, zinc, copper, or nickel.

12. The method of claim 11 , where A is gallium.

13. The method of claim 6 , where A is gallium.

Assignees

• Wisconsin Alumni Res Found

Inventors

• Eom Chang-Beom
• Nan Tianxiang

Classifications

• H01F10/329

  Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect · CPC title

• H01F10/3218

  Exchange coupling of magnetic films via an antiferromagnetic interface (H01F10/3268 takes precedence) · CPC title

• H10N50/85 Primary

  Materials of the active region · CPC title

• H10N50/80

  Constructional details · CPC title

• H10N50/10 Primary

  Magnetoresistive devices · CPC title