Tunable tetragonal ferrimagnetic heusler compound with PMA and high TMR

Patent metadata

Field	Value
Publication number	US-10937953-B2
Application number	US-201916260024-A
Country	US
Kind code	B2
Filing date	Jan 28, 2019
Priority date	Jan 28, 2019
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A device is disclosed. The device includes a tetragonal Heusler compound of the form Mn3-xCoxGe, wherein 0<x≤1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound. The device also includes a substrate oriented in the direction (001) and of the form YMn1+d, wherein Y includes an element selected from the group consisting of Ir and Pt, and 0≤d≤4. The tetragonal Heusler compound and the substrate are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other. In one aspect, the device also includes a multi-layered structure that is non-magnetic at room temperature. The structure includes alternating layers of Co and E. E includes at least one other element that includes Al. The composition of the structure is represented by Co1-yEy, with y being in the range from 0.45 to 0.55.

First claim

What is claimed is:

1. A device, comprising:
a Heusler compound of the form Mn 3-x Co x Ge, wherein 0<x≤1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound and the Heusler compound has a tetragonal structure; and
a substrate oriented in the direction (001) and of the form YMn 1+d , wherein Y includes an element selected from the group consisting of Ir and Pt, and 0≤d≤4,
wherein the Heusler compound and the substrate are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other.

2. The device of claim 1 , wherein Y is Ir.

3. The device of claim 1 , further comprising a tunnel barrier in contact with the Heusler compound.

4. The device of claim 3 , wherein the tunnel barrier includes Mg and O.

5. The device of claim 1 , further comprising a TaN layer between and in contact with the Heusler compound and the substrate.

6. The device of claim 1 , wherein the Heusler compound is of the form Mn 3-x Co x Ge, wherein 0<x≤1, and the substrate is of the form IrMn 3 .

7. The device of claim 1 , wherein the Heusler compound has a magnetic moment that is substantially perpendicular to the film plane.

8. The device of claim 7 , wherein the Heusler compound has a thickness of at least 10 Angstroms and not more than 500 angstroms.

9. The device of claim 1 , wherein a TaN layer is underneath and in contact with the substrate.

10. The device of claim 1 , wherein the Heusler compound has a thickness of less than 5 nm.

11. The device of claim 1 , wherein the Heusler compound has a thickness of less than 3 nm.

12. A device, comprising:
a Heusler compound of the form Mn 3-x Co x Ge, wherein 0<x≤1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound, the Heusler compound having a tetragonal structure;
a multi-layered structure that is non-magnetic at room temperature, the multi-layered structure comprising alternating layers of Co and E, wherein E comprises at least one other element that includes Al, wherein the composition of the structure is represented by Co 1-y E y , with y being in the range from 0.45 to 0.55; and
a substrate underlying the multi-layered structure;
wherein the Heusler compound and the multi-layered structure are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other.

13. The device of claim 12 , wherein the magnetic moment of the Heusler compound is substantially perpendicular to the interface between the multi-layered structure and the Heusler compound.

14. The device of claim 12 , wherein the Heusler compound has a thickness of less than 5 nm.

15. The device of claim 12 , wherein the Heusler compound has a thickness of less than 3 nm.

16. The device of claim 12 , further comprising:
a tunnel barrier overlying the Heusler compound, thereby permitting current to pass through both the tunnel barrier and the Heusler compound.

17. The device of claim 16 , wherein the tunnel barrier includes Mg and O.

18. The device of claim 16 , further comprising a magnetic layer in contact with the tunnel barrier.

19. A device, comprising:
a Heusler compound of the form Mn 3-x Co x Ge, wherein 0<x≤1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound, the Heusler compound having a tetragonal structure;
a multi-layered structure that is non-magnetic at room temperature, the multi-layered structure comprising alternating layers of Co and E, wherein E comprises at least one other element that includes Al, wherein the composition of the structure is represented by Co 1-y E y , with y being in the range from 0.45 to 0.55; and
a substrate underlying the multi-layered structure;
wherein the Heusler compound and the multi-layered structure are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other; and
wherein the Heusler compound has a thickness of one unit cell.

20. A device, comprising:
a Heusler compound of the form Mn 3-x Co x Ge, wherein 0<x≤1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound, the Heusler compound having a tetragonal structure;
a multi-layered structure that is non-magnetic at room temperature, the multi-layered structure comprising alternating layers of Co and E, wherein E comprises at least one other element that includes Al, wherein the composition of the structure is represented by Co 1-y E y , with y being in the range from 0.45 to 0.55; and
a substrate underlying the multi-layered structure;
wherein the Heusler compound and the multi-layered structure are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other; and
wherein E is an AlGe alloy.

21. A device, comprising:
a Heusler compound of the form Mn 3-x Co x Ge, wherein 0<x≤1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound, the Heusler compound having a tetragonal structure;
a multi-layered structure that is non-magnetic at room temperature, the multi-layered structure comprising alternating layers of Co and E, wherein E comprises at least one other element that includes Al, wherein the composition of the structure is represented by Co 1-y E y , with y being in the range from 0.45 to 0.55; and
a substrate underlying the multi-layered structure;
wherein the Heusler compound and the multi-layered structure are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other; and
wherein E is an AlGa alloy.

22. A device, comprising:
a Heusler compound of the form Mn 3-x Co x Ge, wherein 0<x≤1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound, the Heusler compound having a tetragonal structure;
a multi-layered structure that is non-magnetic at room temperature, the multi-layered structure comprising alternating layers of Co and E, wherein E comprises at least one other element that includes Al, wherein the composition of the structure is represented by Co 1-y E y , with y being in the range from 0.45 to 0.55; and
a substrate underlying the multi-layered structure;
wherein the Heusler compound and the multi-layered structure are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other; and
wherein E includes an alloy selected from the group consisting of AlSn, AlGe, AlGaGe, AlGaSn, AlGeSn, and AlGaGeSn.

23. A method, comprising:
using a device as a memory element, the device including
a Heusler compound of the form Mn 3-x Co x Ge, wherein 0<x≤1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound, the Heusler compound having a tetragonal structure; and
a substrate oriented in the direction (001) and of the form YMn 1+d , wherein Y includes an element selected from the group consisting of Ir and Pt, and 0<d≤4;
wherein the Heusler compound and the substrate are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other and
wherein a TaN layer is underneath and in contact with the substrate.

24. A method comprising:
using a device as a memory element, the device including
a first magnetic layer that includes a Heusler compound of the form Mn 3-x Co x Ge, wherein 0<x≤1, wherein Co accounts for at least 0.4 atomic percent of the tetragonal Heusler compound, the Heusler compound having a tetragonal structure; and
a multi-layered structure that

Assignees

• Samsung Electronics Co Ltd
• IBM

Inventors

• Jeong Jaewoo
• Samant Mahesh G
• Parkin Stuart S P
• Ferrante Yari

Classifications

• H01F10/3286

  Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy · CPC title

• H01F10/3254

  the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ] · CPC title

• H01F10/30

  characterised by the composition of the intermediate layers {, e.g. seed, buffer, template, diffusion preventing, cap layers (H01F10/06 and H01F10/32 take precedence)} · CPC title

• H01F10/1936

  Half-metallic, e.g. epitaxial CrO2 or NiMnSb films · CPC title

• G11C11/161 Primary

  details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell · CPC title