Ferrimagnetic Heusler compounds with high spin polarization

1. A magnetic device, comprising:

a multilayer structure including alternating layers of A and E, A including a first material, E including at least one other material that includes Al, the first material including at least one of Ru, Ir, or an IrCo alloy, a composition of the multilayer structure being represented by A 1-x E x , where x is at least 0.45 and not more than 0.55; and

a magnetic layer that includes an Al-doped Heusler compound, the magnetic layer sharing an interface with the multilayer structure.

2. The magnetic device of claim 1 , wherein the Al-doped Heusler compound is represented by H 1-y Al y H, where H is an undoped Heusler compound of the Al-doped Heusler compound, H 1-y is the undoped Heusler compound with a species therein reduced by a factor of 1-y, and y is greater than zero and not more than one.

3. The magnetic device of claim 1 , wherein a magnetic moment of the magnetic layer is substantially perpendicular to the interface.

4. The magnetic device of claim 3 , wherein the magnetic layer has a thickness of not more than 5 nm.

5. The magnetic device of claim 1 , wherein the Al-doped Heusler compound includes Al and a Heusler compound, the Heusler compound of the Al-doped Heusler compound is a binary Heusler compound.

6. The magnetic device of claim 5 , wherein the Heusler compound includes at least one of Mn 3.3-z Ge, Mn 3.3-z Sn, or Mn 3.3-y Sb, where z is at least 0 and not more than 0.8 and where y is at least 0 and not more than 1.3.

7. The magnetic device of claim 1 , wherein the first material includes an IrCo alloy.

8. The magnetic device of claim 1 , wherein the at least one other material includes an alloy selected from AlGa, AlSn, AlGe, AlGaGe, AlGaSn, AlGeSn, and AlGaGeSn.

9. The magnetic device of claim 1 , further comprising:

a layer underlying the multilayer structure, the layer including at least one of a Mn y N layer or a V z N layer, where y is at least two and not more than five and z is at least 0.7 and not 10 more than 1.3.

10. The device of claim 9 , wherein the device is a racetrack memory device.

11. The magnetic device of claim 9 , further comprising:

a tunnel barrier; and

an additional magnetic layer in contact with the tunnel barrier, the tunnel barrier being between the magnetic layer and the additional magnetic layer.

12. The magnetic device of claim 11 , wherein the tunnel barrier is selected from MgO or Mg 1-z Al 2+(2/3)z O 4 , wherein −0.5≤z≤0.5.

13. A device, comprising:

a plurality of magnetic junctions, each of the plurality of magnetic junctions including a multilayer structure, a magnetic layer, an additional magnetic layer, and tunnel barrier between the magnetic layer and the additional magnetic layer, the multilayer structure including alternating layers of A and E, A including a first material, E including at least one other material that includes Al, the first material including at least one of Ru, Ir, or an IrCo alloy, a composition of the multilayer structure being represented by A 1-x E x , where x is at least 0.45 and not more than 0.55, the magnetic layer including an Al-doped Heusler compound, the magnetic layer sharing an interface with the multilayer structure, the additional magnetic layer being in contact with the tunnel barrier; and

a plurality of conductive lines coupled with the plurality of magnetic junctions.

14. The device of claim 13 , wherein the Al-doped Heusler compound is represented by H 1-y Al y , where H is an undoped Heusler compound of the Al-doped Heusler compound, H 1-y is the undoped Heusler compound having a species therein reduced by a factor of 1-y, and y is greater than zero and not more than one.

15. The device of claim 13 , wherein a Heusler compound of the Al-doped Heusler compound includes Mn and an element selected from the group consisting of Sn, Sb, or Ge.

16. The device of claim 15 , wherein the Heusler compound includes at least one of Mn 3.3-z Ge, Mn 3.3-z Sn, or Mn 3.3-y Sb, where z is at least 0 and not more than 0.8 and where y is at least 0 and not more than 1.3.

17. The device of claim 14 , wherein each of the plurality of magnetic junctions further includes:

a layer underlying the multilayer structure, the layer including at least one of a Mn y N layer or a V z N layer, where y is at least two and not more than five and z is at least 0.7 and not more than 1.3.

18. A method, comprising:

providing a multilayer structure including alternating layers of A and E, A including a first material, E including at least one other material that includes Al, the first material including at least one of Ru, Ir, or an IrCo alloy, a composition of the multilayer structure being represented by A 1-x E x , where x is at least 0.45 and not more than 0.55; and

providing a magnetic layer on the multilayer structure, the magnetic layer including an Al-doped Heusler compound, the magnetic layer sharing an interface with the multilayer structure.

19. The method of claim 18 , further comprising:

providing a layer interposed including at least one of a Mn y N layer or a V z N layer, the layer underlying the multilayer structure, where y is at least two and not more than five and z is at least 0.7 and not more than 1.3.

20. The method of claim 18 , further comprising:

providing a tunnel barrier; and

providing an additional magnetic layer in contact with the tunnel barrier, the tunnel barrier being between the magnetic layer and the additional magnetic layer.