Top-pinned magnetoresistive device having adjusted interface property
View Patent ↗A top-pinned magnetoresistive device includes a free ferromagnetic layer; a spacer layer on the free layer; and a pinned ferromagnetic layer on the spacer layer. At least one interface property at an upper surface of the pinned layer is adjusted during fabrication of the magnetoresistive device.
1. A magnetoresistive device comprising:
a free ferromagnetic layer;
a spacer layer on the free ferromagnetic layer; and
a pinned ferromagnetic layer on the spacer layer, the pinned layer having at least one interface property adjusted by ion etching to improve exchange coupling in the device;
wherein the magnetoresistive device is top-pinned.
2. The device of claim 1 , further comprising an AF pinning layer on the pinned layer; wherein the at least one interface property is adjusted to increase exchange coupling between the pinned and pinning layers.
3. The device of claim 1 , wherein the at least one interface property also adjusts magnetic characteristics of the device.
4. The device of claim 3 , wherein the magnetic characteristics include a shifted H-M loop of the free layer loop to compensate for FM coupling between the free and pinned layer.
5. The device of claim 3 , wherein the magnetic characteristics include the squareness of H-M loops of the free and pinned layer.
6. The device of claim 1 , wherein the at least one interface property is adjusted to increase coercivity of the free layer.
7. The device of claim 1 , wherein the at least one interface property includes surface texture and grain size.
8. The device of claim 1 , wherein the spacer layer includes an insulating tunnel barrier.
9. The device of claim 1 , further comprising an interfacial layer on the free ferromagnetic layer, the interfacial layer having at least one adjusted interface property.
10. The device of claim 1 , wherein the free layer and pinned layers are made of amorphous FM material.
11. The device of claim 1 , wherein the spacer layer includes an insulating tunnel barrier.
12. An information storage device including at least one magnetoresistive device of claim 1 .
13. A memory cell including the device of claim 1 .
14. An MRAM device including an array of memory cells, each memory cell including at least one device of claim 1 .
15. A read head for a hard drive, the read head including the device of claim 1 .
16. A hard disk drive including at least one device of claim 1 .
17. A magnetoresistive device comprising:
a free ferromagnetic layer;
a spacer layer on the free ferromagnetic layer;
a pinned ferromagnetic layer on the spacer layer; and
an antiferromagnetic pinning layer on the pinned layer;
the pinned and pinning layers forming an interface, the interface having been ion etched to improve exchange coupling between the pinned and pinning layers.
18. A method of forming the magnetoresistive device of claim 1 , the method comprising:
forming the free ferromagnetic layer;
forming the spacer layer on the free layer;
forming the pinned ferromagnetic layer on the spacer layer; and adjusting the at least one interface property at an upper surface of the pinned layer.
19. The method of claim 1 , further comprising depositing an AF pinning layer on the pinned layer; wherein the at least one interface property is adjusted to increase exchange coupling between the pinned and pinning layers.
20. The method of claim 1 , wherein the at least one interface property is adjusted to shift an H-M loop of the free layer loop to compensate for FM coupling between the free and pinned layers.
21. The method of claim 1 , wherein the at least one interface property is adjusted to improve squareness of H-M loops of the free and pinned layers.
22. The method of claim 1 , wherein the at least one interface property is adjusted to adjust magnetic characteristics of the free layer.
23. The method of claim 22 , wherein the magnetic characteristics include FM coupling.
24. The method of claim 22 , wherein the magnetic characteristics include coercivity of the free layer.
25. The method of claim 1 , wherein the adjusting includes adjusting texture of the upper surface.
26. The method of claim 1 , wherein the adjusting includes filling in grain boundaries at the upper surface of the pinned layer.
27. The method of claim 1 , wherein at least some magnetic characteristics of the device are controlled by controlling ion etch rate and duration.
28. The method of claim 1 , further comprising forming an interfacial layer on the pinned layer; and adjusting at least one interface property at an upper surface of the interfacial layer.
29. The method of claim 1 , wherein forming the spacer layer includes forming an insulating tunnel barrier.
30. The method of claim 1 , wherein the free layer is not seeded.