Magnetic memory device with stack structure including first and second magnetic layers and nonmagnetic layer between the first and second magnetic layers

1. A magnetic memory device comprising a stack structure including a first magnetic layer having a variable magnetization direction, a second magnetic layer having a fixed magnetization direction, and a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer,

wherein the second magnetic layer includes a first layer containing iron (Fe) and boron (B), a second layer containing iron (Fe) and boron (B), and a third layer provided between the first layer and the second layer and containing a semiconductor in an entire region thereof, wherein the third layer is in physical contact with both the first layer and the second layer, and wherein the third layer has a semiconductor concentration higher than a semiconductor concentration of the first layer and a semiconductor concentration of the second layer.

2. The device of claim 1 , wherein the semiconductor of the third layer includes at least one group-4 semiconductor element.

3. The device of claim 2 , wherein the at least one group-4 semiconductor element includes at least one of silicon (Si) and germanium (Ge).

4. The device of claim 1 , wherein the semiconductor of the third layer includes a compound semiconductor.

5. The device of claim 1 , wherein the third layer further contains iron (Fe) and boron (B).

6. The device of claim 5 , wherein the third layer further contains cobalt (Co).

7. The device of claim 1 , wherein the first layer further contains cobalt (Co).

8. The device of claim 1 , wherein the second layer further contains cobalt (Co).

9. The device of claim 1 , wherein the first layer contacts the nonmagnetic layer.

10. The device of claim 1 , wherein the second magnetic layer further includes a fourth layer containing a material which is different from a material of the first layer, a material of the second layer, and a material of the third layer, and

wherein the first layer, the second layer, and the third layer are provided between the nonmagnetic layer and the fourth layer.

11. The device of claim 10 , wherein the fourth layer includes a layer containing an element selected from Tb, Dy, and Gd, and an element selected from Co and Fe, and

wherein magnetization of the first layer, the second layer, and the third layer and magnetization of the fourth layer are coupled in an antiparallel manner.

12. The device of claim 1 , wherein the second magnetic layer further includes a fifth layer provided between the nonmagnetic layer and the first, second, and third layers, the fifth layer containing a semiconductor.

13. The device of claim 1 , wherein the nonmagnetic layer contains magnesium (Mg), silicon (Si), and oxygen (O).

14. The device of claim 13 , wherein concentration of magnesium (Mg) is higher on the first magnetic layer side than on the second magnetic layer side in the nonmagnetic layer.

15. The device of claim 13 , wherein concentration of silicon (Si) is higher on the second magnetic layer side than on the first magnetic layer side in the nonmagnetic layer.

16. The device of claim 13 , wherein the nonmagnetic layer includes a crystal structure.

17. The device of claim 13 , wherein the nonmagnetic layer includes an oxygen deficiency structure.

18. The device of claim 1 , wherein the first magnetic layer contains iron (Fe) and boron (B).

19. The device of claim 18 , wherein the first magnetic layer further contains cobalt (Co).

20. The device of claim 1 , wherein the first magnetic layer has a magnetization direction perpendicular to a main surface thereof, and

wherein the second magnetic layer has a magnetization direction perpendicular to a main surface thereof.