Magnetic coupling layers, structures comprising magnetic coupling layers and methods for fabricating and/or using same

Patent metadata

Field	Value
Publication number	US-11025200-B2
Application number	US-201916562337-A
Country	US
Kind code	B2
Filing date	Sep 5, 2019
Priority date	Mar 10, 2017
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

A magnetic structure is provided. The magnetic structure may have a first magnetic layer with a first magnetization direction, a second magnetic layer with a second magnetization direction and a coupling layer interposed between the first and second magnetic layers. The coupling layer may include at least one non-magnetic element and at least one magnetic element. The atomic ratio of the at least one non-magnetic element to the at least one magnetic element is (100−x):x, where x is an atomic concentration parameter. Atomic concentration parameter, x, may cause the first magnetic layer to be non-collinearly coupled to the second magnetic layer such that, in the absence of external magnetic field, the first magnetization direction is oriented at a non-collinear angle relative to the second magnetization direction.

First claim

The invention claimed is:

1. A magnetic structure comprising:
a first magnetic layer having a first magnetization direction;
a second magnetic layer having a second magnetization direction;
a coupling layer interposed between the first magnetic layer and the second magnetic layer, the coupling layer comprising:
at least one non-magnetic element selected from the group consisting of: Ag, Cr, Ru, Mo, Ir, Rh, Cu, V, Nb, W, Ta, Ti, Re, Os, Au, Al and Si; and
at least one magnetic component selected from the group consisting of at least one magnetic element, at least one magnetic compound, and any combination thereof,
wherein the at least one magnetic element is selected from the group consisting of Ni, Co, and Fe, and
wherein the at least one magnetic compound is selected from the group consisting of NiPt, NiPd, CoPt, CoPd, FePt, and FePd;

wherein a composition of the coupling layer provides non-collinear coupling between the first magnetic layer and the second magnetic layer;
wherein an atomic ratio of the at least one non-magnetic element to the at least one magnetic component is (100−x):x; and
wherein x is an atomic concentration parameter which causes, or is selected to cause, the first magnetic layer to be non-collinearly coupled to the second magnetic layer such that, in the absence of external magnetic field, the first magnetization direction is oriented at a non-collinear angle relative to the second magnetization direction; and
wherein said composition excludes the group consisting of:
RuCo alloys where atomic concentration of Co is less than 40;
RuCoCr alloys where atomic concentration of Co is less than 40;
CoCr alloys where atomic concentration of Co is less than 60; and
CoCrB alloys where atomic concentration of Co is less than 60.

2. The magnetic structure according to claim 1 wherein the coupling layer has a thickness, t c , and wherein a combination of the atomic concentration parameter x and the thickness t c of the coupling layer causes, or is selected to cause, the first magnetic layer to be non-collinearly coupled to the second magnetic layer.

3. The magnetic structure according to claim 2 wherein:
the at least one non-magnetic element comprises Ru;
the at least one magnetic component comprises the at least one magnetic element,
and the at least one magnetic element comprises Co;
x is between 40 and 64; and
t c is greater than 0.4 nm and less than 1.8 nm.

4. The magnetic structure according to claim 2 wherein:
the at least one non-magnetic substance comprises Ru;
the at least one magnetic component comprises the at least one magnetic element,
and the at least one magnetic element comprises Fe;
x is between 66 and 82; and
t c is greater than 0.4 nm and less than 1.8 nm.

5. The magnetic structure according to claim 2 wherein:
the at least one non-magnetic element comprises Ru;
the at least one magnetic component comprises the at least one magnetic element, and the at least one magnetic element comprises Co and Fe;
x is between 40 and 94 and is dependent on the ratio of Co:Fe; and
t c is greater than 0.4 nm and less than 1.8 nm.

6. The magnetic structure according to claim 2 , wherein the at least one non-magnetic element that comprises the coupling layer is Ru.

7. The magnetic structure according to claim 1 wherein the at least one non-magnetic element is selected from the group consisting of Ru, Ir, Re, Rh, and Cr.

8. The magnetic structure according to claim 1 wherein the at least one non-magnetic element comprises Ru.

9. The magnetic structure according to claim 1 wherein the magnetic structure is annealed at a temperature of at least 200° C. and after annealing, the first magnetic layer is non-collinearly coupled to the second magnetic layer.

10. The magnetic structure according to claim 1 further comprising Mn wherein the at least one magnetic component comprises the at least one magnetic element, and wherein the atomic concentration parameter x reflects the combined atomic concentration of Mn and the at least one magnetic element.

11. The magnetic structure according to claim 1 wherein:
the at least one magnetic component selected from the at least one magnetic element.

12. A method for fabricating the magnetic structure according to claim 1 , the method comprising:
layering a coupling layer between a first magnetic layer having a first magnetization direction and a second magnetic layer having a second magnetization direction, the coupling layer comprising:
at least one non-magnetic element selected from frons the group consisting of: Ag, Cr, Ru, Mo, Ir, Rh, Cu, V, Nb, W, Ta, Ti, Re, Os, Au, Al and Si; and
at least one magnetic component selected from the group consisting of at least one magnetic element, at least one magnetic compound, and any combination thereof, wherein the at least one magnetic element is selected from the group consisting of Ni, Co, and Fe, and wherein the at least one magnetic compound is selected from the group consisting of NiPt, NiPd, CoPt, CoPd, FePt, and FePd;
wherein a composition of the coupling layer provides non-collinear coupling between the first magnetic layer and the second magnetic layer;
wherein the atomic ratio of the at least one non-magnetic element to the at least one magnetic component is (100−x):x; and
wherein x is an atomic concentration parameter and x is selected such that the first magnetic layer is non-collinearly coupled to the second magnetic layer, such that, in the absence of external magnetic field, the first magnetization direction is oriented at a non-collinear angle relative to the second magnetization direction
wherein said composition excludes the group consisting of:
RuCo alloys where atomic concentration of Co is less than 40;
RuCoCr alloys where atomic concentration of Co is less than 40;
CoCr alloys where atomic concentration of Co is less than 60; and
CoCrB alloys where atomic concentration of Co is less than 60.

13. The method according to claim 12 wherein layering the coupling layer between the first magnetic layer and the second magnetic layer comprises:
depositing the coupling layer on the first magnetic layer and wherein depositing the coupling layer on the first magnetic layer comprises using a chemical vapor deposition (CVD), atomic layer deposition (ALD) or physical vapor deposition (PVD) process; and
depositing the second magnetic layer on the coupling layer.

14. The method according to claim 13 further comprising annealing the magnetic structure after depositing the coupling layer on the first magnetic layer and depositing the second magnetic layer on the coupling layer.

15. The method according to claim 12 wherein layering the coupling layer between the first magnetic layer and the second magnetic layer comprises:
depositing an intermediate layer comprising the at least one non-magnetic element on the first magnetic layer;
depositing the second magnetic layer on the intermediate layer; and
annealing the resultant structure comprising the first magnetic layer, the intermediate layer and the second magnetic layer and thereby diffusing the at least one magnetic element from the first and second magnetic layers into the intermediate layer to thereby form the coupling layer.

16. The magnetic structure according to claim 1 , further comprising:
a third magnetic layer having a third magnetization direction;
a magnetoresistive layer interposed between the third magnetic layer and the second magnetic layer; and
a circuit connected to the third magnetic layer and the first magnetic layer to determine a change in resistanc

Assignees

• Univ Fraser Simon

Inventors

• Nunn Zachary Raymond
• Girt Erol

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

• G01R33/093

  using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00) · CPC title

• G11C11/161

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

• H01F10/3272

  by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets · CPC title

• G01R33/098

  comprising tunnel junctions, e.g. tunnel magnetoresistance sensors · CPC title