SOT film stack for differential reader
The present disclosure generally relates to spin-orbital torque (SOT) differential reader designs. The SOT differential reader is a multi-terminal device comprising a first seed layer, a first spin hall effect (SHE) layer, a first interlayer, a first free layer, a gap layer, a second seed layer, a second SHE layer, a second free layer, and a second interlayer. The gap layer is disposed between the first SHE layer and the second SHE layer. The materials and dimensions used for the first and second seed layers, the first and second interlayers, and the first and second SHE layers affect the resulting spin hall voltage converted from spin current injected from the first free layer and the second free layer, as well as the ability to tune the first and second SHE layers. Moreover, the SOT differential reader improves reader resolution without decreasing the shield-to-shield spacing (i.e., read-gap).
1. A magnetic sensor, comprising:
a first spin hall effect layer comprising BiSb or an alloy thereof having a crystalline structure of (012);
a second spin hall effect layer comprising BiSb or an alloy thereof having a crystalline structure of (001); and
a gap layer disposed between the first spin hall effect layer and the second spin hall effect layer.
2. The magnetic sensor of claim 1 , wherein the first spin hall effect layer and the second spin hall effect layer have the same thickness.
3. The magnetic sensor of claim 1 , wherein the gap layer has a smaller thickness than the first spin hall effect layer.
4. A magnetic recording device comprising the magnetic sensor of claim 1 .
5. A magnetic sensor, comprising:
a first spin hall effect layer comprising BiSb or an alloy thereof;
a second spin hall effect layer;
a third spin hall effect layer comprising BiSb or an alloy thereof;
a fourth spin hall effect layer; and
a gap layer disposed between the first spin hall effect layer and the third spin hall effect layer.
6. The magnetic sensor of claim 5 , wherein the gap layer is disposed between the second spin hall effect layer and the fourth spin hall effect layer.
7. The magnetic sensor of claim 5 , wherein the second spin hall effect layer comprises BiSb or an alloy thereof.
8. The magnetic sensor of claim 7 , wherein the fourth spin hall effect layer comprises BiSb or an alloy thereof.
9. The magnetic sensor of claim 5 , wherein the gap layer comprises a non-magnetic conducing material.
10. The magnetic sensor of claim 9 , wherein the non-magnetic conducting material comprises Cr.
11. A magnetic recording device comprising the magnetic sensor of claim 5 .
12. A magnetic sensor, comprising:
a first spin hall effect layer having a crystalline structure of (012);
a second spin hall effect layer;
a third spin hall effect layer having a crystalline structure of (001);
a fourth spin hall effect layer; and
a gap layer disposed between the first spin hall effect layer and the third spin hall effect layer.
13. The magnetic sensor of claim 12 , wherein the second spin hall effect layer has a crystalline structure of (012).
14. The magnetic sensor of claim 13 , wherein the fourth spin hall effect layer has a crystalline structure of (001).
15. The magnetic sensor of claim 12 , further comprising:
a first free layer; and
a second free layer, wherein the gap layer is disposed between the first free layer and the second free layer.
16. The magnetic sensor of claim 15 , wherein the gap layer is disposed in contact with the first free layer and the second free layer.
17. The magnetic sensor of claim 15 , wherein the first free layer and the second free layer comprise the same material.
18. The magnetic sensor of claim 17 , wherein the same material comprise a multilayer stack.
19. The magnetic sensor of claim 18 , wherein the multilayer stack comprises CoFe/CoFeB/Ta/NiFe.
20. A magnetic recording device comprising the magnetic sensor of claim 12 .