Templating layers for forming highly textured thin films of heusler compounds switchable by application of spin transfer torque
A device and method for providing the device are described. The device includes a substrate, a Mn x N layer overlying the substrate, a multi-layered structure that is non-magnetic at room temperature and a first magnetic layer. The Mn x N layer has 2≤x≤4.75. The multi-layered structure comprises alternating layers of Co and E, wherein E comprises at least one other element that includes Al. The composition of the multi-layered structure is represented by Co 1-x E x , with x being in the range from 0.45 to 0.55. The first magnetic layer includes a Heusler compound. The first magnetic layer is in contact with the multi-layered structure and the first magnetic layer forms part of a magnetic tunnel junction.
1. A device, comprising:
a substrate;
a Mn x N layer overlying the substrate wherein 2≤x≤4.75;
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 at least one of Ge, Ga, Sn and Al, wherein a composition of the multi-layered structure is represented by Co 1-y E y , with y being in a range from 0.45 to 0.55, the multi-layered structure overlying the Mn x N layer; and
a first magnetic layer that includes a Heusler compound having a perpendicular magnetic anisotropy, wherein:
the first magnetic layer is in contact with the multi-layered structure, the multi-layered structure being between the Mn x N layer and the first magnetic layer, and
the first magnetic layer forms part of a magnetic tunnel junction.
2. The device of claim 1 , wherein the magnetic moment of the first magnetic layer is substantially perpendicular to the interface between the multi-layered structure and the first magnetic layer.
3. The device of claim 2 , wherein the first magnetic layer has a thickness of less than 5 nm.
4. The device of claim 2 , wherein the first magnetic layer has a thickness of less than 3 nm.
5. The device of claim 2 , wherein the first magnetic layer has a thickness of one unit cell.
6. The device of claim 1 , wherein the Heusler compound is selected from the group consisting of Mn 3.1-z Ge, Mn 3.1-z Sn, Mn 3.1-z Sb and Mn 3.1-s Co 1.1-t Sn, with z being in an additional range from 0 to 1.1 and wherein s≤1.2 and t≤1.0.
7. The device of claim 1 , wherein the Heusler compound is a ternary Heusler.
8. The device of claim 1 , wherein the Heusler compound is a Mn-based Heusler compound.
9. The device of claim 1 , wherein E is Ge.
10. The device of claim 1 , wherein E is Ga.
11. The device of claim 1 , comprising a tunnel barrier overlying the first magnetic layer, thereby permitting current to pass through both the tunnel barrier and the first magnetic layer.
12. The device of claim 11 , comprising a second magnetic layer in contact with the tunnel barrier.
13. The device of claim 12 , wherein the tunnel barrier is MgO.
14. The device of claim 12 , wherein the tunnel barrier is Mg 1-z Al 2-z O 4 , wherein −0.5<z<0.5.
15. A method, comprising:
using a device as a memory element, the device including a substrate, a Mn x N layer overlying the substrate wherein 2≤x≤4.75, a multi-layered structure that is non-magnetic at room temperature, a first magnetic layer, a tunnel barrier and a second magnetic layer, the tunneling barrier being between the first magnetic layer and the second magnetic layer, the second magnetic layer being in contact with the tunnel barrier, the multi-layered structure comprising alternating layers of Co and E, wherein E comprises at least one other element that includes at least one of Ge, Ga and Al, wherein a composition of the multi-layered structure is represented by Co 1-y E y , with y being in a range from 0.45 to 0.55, the multi-layered structure overlying the Mn x N layer, the first magnetic layer including a Heusler compound having a perpendicular magnetic anisotropy, wherein the first magnetic layer is in contact with the multi-layered structure, the multi-layered structure being between the Mn x N layer and the first magnetic layer, wherein the first magnetic layer forms part of a magnetic tunnel junction, wherein the tunnel barrier permits current to pass through both the tunnel barrier and the first magnetic layer.
16. The method of claim 15 , wherein the memory element is part of a racetrack memory device.
17. A device, comprising:
a substrate;
a Mn x N layer overlying the substrate wherein 2≤x≤4.75;
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 at least one of Ge, Ga, Sn and Al, wherein a composition of the multi-layered structure is represented by Co 1-z E z , with z being in a range from 0.45 to 0.55, the multi-layered structure overlying the Mn x N layer;
a first magnetic layer that includes a Heusler compound, the first magnetic layer being in contact with the multi-layered structure, the multi-layered structure being between the Mn x N layer and the first magnetic layer, wherein the first magnetic layer has a magnetic moment that is switchable, the Heusler compound having a perpendicular magnetic anisotropy;
a tunnel barrier overlying the first magnetic layer; and
a second magnetic layer in contact with the tunnel barrier, wherein:
the first magnetic layer, the tunnel barrier, and the second magnetic layer form at least part of a magnetic tunnel junction.
18. The device of claim 17 , comprising a capping layer in contact with the second magnetic layer.
19. The device of claim 17 , wherein the first magnetic layer includes Mn and an element selected from the group consisting of Sn, Sb, and Ge.
20. The device of claim 17 , wherein the first magnetic layer further includes Co.
21. A device, comprising:
a substrate;
a Mn x N layer overlying the substrate wherein 2≤x≤4.75;
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 at least one of Ge, Ga, Sn and Al, wherein a composition of the multi-layered structure is represented by Co 1-z E z , with z being in a range from 0.45 to 0.55, wherein the multi-layered structure overlies the substrate, the multi-layered structure overlying the Mn x N layer;
a first magnetic layer that includes a Heusler compound, the first magnetic layer being in contact with the multi-layered structure, the multi-layered structure being between the Mn x N layer and the first magnetic layer, the Heusler compound having a perpendicular magnetic anisotropy.
22. The device of claim 21 , comprising a capping layer in contact with the first magnetic layer.
23. The device of claim 1 , wherein E is Al.