Spin injection magnetization reversal element
View Patent ↗A spin injection magnetization reversal element includes a ferromagnetic fixed layer, an isolation layer and a ferromagnetic free layer. The area of contact between the ferromagnetic fixed layer and the isolation layer is larger than an area of contact between the ferromagnetic free layer and the isolation layer. The ferromagnetic fixed layer may be divided into ferromagnetic first fixed layer and ferromagnetic second fixed layer, and the isolation layer may be divided into first isolation layer and second isolation layer. The ferromagnetic first fixed layer may be arranged on one of opposed principal surfaces of the ferromagnetic free layer with the first isolation layer in between, and the ferromagnetic second fixed layer may be arranged on the other of the opposed principal surfaces of the ferromagnetic free layer with the second isolation layer in between. The element holds recorded magnetization and can reverse magnetization with a small current density.
1. A spin injection magnetization reversal element comprising, in order, a ferromagnetic fixed layer, an isolation layer and a ferromagnetic free layer, in which element flow of a current between the ferromagnetic fixed layer and the ferromagnetic free layer causes transition between a state in which the direction of the magnetization of the ferromagnetic fixed layer and the direction of the magnetization of the ferromagnetic free layer are in parallel with each other and a state in which the directions of the magnetization are in antiparallel with each other,
wherein the ferromagnetic fixed layer surrounds the ferromagnetic free layer,
wherein a free layer electrode is electrically connected to the ferromagnetic free layer apart from the ferromagnetic fixed layer and a fixed layer electrode is electrically connected to the ferromagnetic fixed layer apart from the ferromagnetic free layer, and
wherein an area with which the ferromagnetic fixed layer is in contact with the isolation layer is larger than an area with which the ferromagnetic free layer is in contact with the isolation layer.
2. The spin injection magnetization reversal element according to claim 1 , wherein an electrode is connected onto one surface of the ferromagnetic free layer, and the ferromagnetic fixed layer is arranged on the other surfaces of the ferromagnetic free layer with the isolation layer in between.
3. A spin injection magnetization reversal element comprising a ferromagnetic fixed layer, an isolation layer and a ferromagnetic free layer, in which element flow of a current between the ferromagnetic fixed layer and the ferromagnetic free layer causes transition between a state in which the direction of the magnetization of the ferromagnetic fixed layer and the direction of the magnetization of the ferromagnetic free layer are in parallel with each other and a state in which the directions of the magnetization are in antiparallel with each other,
wherein the ferromagnetic fixed layer is divided into a ferromagnetic first fixed layer and a ferromagnetic second fixed layer, the isolation layer is divided into a first isolation layer and a second isolation layer, the ferromagnetic first fixed layer is arranged on one of opposed principal surfaces of the ferromagnetic free layer with the first isolation layer in between, the ferromagnetic second fixed layer is arranged on the other of the opposed principal surfaces of the ferromagnetic free layer with the second isolation layer put between, and the ferromagnetic first fixed layer and the ferromagnetic second fixed layer are in direct contact with each other.
4. The spin injection magnetization reversal element according to claim 1 , wherein a product of the magnetization and the volume of the ferromagnetic fixed layer is larger than a product of the magnetization and the volume of the ferromagnetic free layer.
5. The spin injection magnetization reversal element according to claim 3 , wherein a product of the magnetization and the volume of the ferromagnetic fixed layer is larger than a product of the magnetization and the volume of the ferromagnetic free layer.
6. The spin injection magnetization reversal element according to claim 1 , wherein the saturation magnetization of the ferromagnetic free layer is smaller than the saturation magnetization of the ferromagnetic fixed layer.
7. The spin injection magnetization reversal element according to claim 3 , wherein the saturation magnetization of the ferromagnetic free layer is smaller than the saturation magnetization of the ferromagnetic fixed layer.
8. The spin injection magnetization reversal element according to claim 1 , wherein the coercive force of the ferromagnetic free layer is smaller than the coercive force of the ferromagnetic fixed layer.
9. The spin injection magnetization reversal element according to claim 3 , wherein the coercive force of the ferromagnetic free layer is smaller than the coercive force of the ferromagnetic fixed layer.
10. The spin injection magnetization reversal element according to claim 1 , wherein the ferromagnetic fixed layer is connected to a plurality of electrodes conducting one another.
11. The spin injection magnetization reversal element according to claim 3 , wherein the ferromagnetic fixed layer is connected to a plurality of electrodes conducting one another.
12. The spin injection magnetization reversal element according to claim 1 , wherein the isolation layer is made of nonmagnetic metal.
13. The spin injection magnetization reversal element according to claim 3 , wherein the isolation layer is made of nonmagnetic metal.
14. The spin injection magnetization reversal element according to claim 1 , wherein the isolation layer is made of insulation material.
15. The spin injection magnetization reversal element according to claim 3 , wherein the isolation layer is made of insulation material.
16. The spin injection magnetization reversal element according to claim 1 , wherein the isolation layer is made of copper.
17. The spin injection magnetization reversal element according to claim 3 , wherein the isolation layer is made of copper.
18. The spin injection magnetization reversal element according to claim 1 , wherein the isolation layer is made of aluminum oxide.
19. The spin injection magnetization reversal element according to claim 3 , wherein the isolation layer is made of aluminum oxide.
20. The spin injection magnetization reversal element according to claim 1 , wherein the ferromagneitc fixed layer and the ferromagnetic free layer are made of metallic cobalt.
21. The spin injection magnetization reversal element according to claim 3 , wherein the ferromagneitc fixed layer and the ferromagnetic free layer are made of metallic cobalt.
22. The spin injection magnetization reversal element according to claim 2 , wherein an electrode is connected onto one surface of the ferromagnetic fixed layer, and the ferromagnetic free layer is arranged on the other surface of the ferromagnetic fixed layer with the isolation layer in between.