Magnetic memory device
View Patent ↗According to one embodiment, a magnetic memory device includes a first magnetic layer selectively exhibiting a first state in which the first magnetic layer has a first magnetization direction perpendicular to a main surface thereof and a second state in which the first magnetic layer has a second magnetization direction opposite to the first magnetization direction, a second magnetic layer having a fixed magnetization direction perpendicular to a main surface thereof and corresponding to the first magnetization direction, a third magnetic layer provided between the first and second magnetic layers, having a fixed magnetization direction perpendicular to a main surface thereof and corresponding to the second magnetization direction, and having a side surface including a recess portion, and a nonmagnetic layer provided between the first and third magnetic layers.
1. A magnetic memory device comprising:
a first magnetic layer selectively exhibiting a first state in which the first magnetic layer has a first magnetization direction perpendicular to a main surface thereof and a second state in which the first magnetic layer has a second magnetization direction opposite to the first magnetization direction;
a second magnetic layer having a fixed magnetization direction which is perpendicular to a main surface thereof and which corresponds to the first magnetization direction;
a third magnetic layer provided between the first magnetic layer and the second magnetic layer, the third magnetic layer having a fixed magnetization direction which is perpendicular to a main surface thereof and which corresponds to the second magnetization direction, and having a side surface including a recess portion; and
a nonmagnetic layer provided between the first magnetic layer and the third magnetic layer,
wherein the side surface of the third magnetic layer except the recess portion aligns with a side surface of the first magnetic layer.
2. The device of claim 1 , further comprising:
an inactive portion provided in the recess portion, the inactive portion being magnetically inactive.
3. The device of claim 2 , wherein the inactive portion is formed of an oxide.
4. The device of claim 2 , wherein the inactive portion is formed of an oxide of a material used for the third magnetic layer.
5. The device of claim 2 , wherein the inactive portion has an amorphous structure and is formed of a material substantially the same as a material used for the third magnetic layer.
6. The device of claim 2 , wherein the inactive portion is in contact with the nonmagnetic layer.
7. The device of claim 1 , wherein an inner surface of the recess portion is defined by the third magnetic layer and the nonmagnetic layer.
8. The device of claim 1 , wherein the recess portion has a ring shape when viewed from a direction perpendicular to the main surface of the third magnetic layer.
9. The device of claim 1 , wherein the side surface of the third magnetic layer except the recess portion aligns with a side surface of the second magnetic layer.
10. The device of claim 1 , wherein a structure including the first magnetic layer, the second magnetic layer, the third magnetic layer and the nonmagnetic layer constitutes a spin-transfer-torque (STT) magnetoresistive element.
11. A magnetic memory device comprising:
a first magnetic layer selectively exhibiting a first state in which the first magnetic layer has a first magnetization direction perpendicular to a main surface thereof and a second state in which the first magnetic layer has a second magnetization direction opposite to the first magnetization direction;
a second magnetic layer having a fixed magnetization direction which is perpendicular to a main surface thereof and which corresponds to the first magnetization direction;
a third magnetic layer provided between the first magnetic layer and the second magnetic layer, the third magnetic layer having a fixed magnetization direction which is perpendicular to a main surface thereof and which corresponds to the second magnetization direction, and having a side surface including a recess portion;
a nonmagnetic layer provided between the first magnetic layer and the third magnetic layer; and
an inactive portion provided in the recess portion, the inactive portion being magnetically inactive,
wherein the inactive portion has an amorphous structure and is formed of a material substantially the same as a material used for the third magnetic layer.
12. The device of claim 11 , wherein an inner surface of the recess portion is defined by the third magnetic layer and the nonmagnetic layer.
13. The device of claim 11 , wherein the recess portion has a ring shape when viewed from a direction perpendicular to the main surface of the third magnetic layer.
14. The device of claim 11 , wherein the side surface of the third magnetic layer except the recess portion aligns with a side surface of the second magnetic layer.
15. The device of claim 11 , wherein a structure including the first magnetic layer, the second magnetic layer, the third magnetic layer and the nonmagnetic layer constitutes a spin-transfer-torque (STT) magnetoresistive element.
16. A magnetic memory device comprising:
a first magnetic layer selectively exhibiting a first state in which the first magnetic layer has a first magnetization direction perpendicular to a main surface thereof and a second state in which the first magnetic layer has a second magnetization direction opposite to the first magnetization direction;
a second magnetic layer having a fixed magnetization direction which is perpendicular to a main surface thereof and which corresponds to the first magnetization direction;
a third magnetic layer provided between the first magnetic layer and the second magnetic layer, the third magnetic layer having a fixed magnetization direction which is perpendicular to a main surface thereof and which corresponds to the second magnetization direction, and having a side surface including a recess portion; and
a nonmagnetic layer provided between the first magnetic layer and the third magnetic layer,
wherein a side surface of the first magnetic layer is located outside a side surface of the second magnetic layer and the side surface of the third magnetic layer when viewed from a direction perpendicular to the main surface of the first magnetic layer.
17. The device of claim 16 , further comprising:
an inactive portion provided in the recess portion, the inactive portion being magnetically inactive.
18. The device of claim 16 , wherein an inner surface of the recess portion is defined by the third magnetic layer and the nonmagnetic layer.
19. The device of claim 16 , wherein the recess portion has a ring shape when viewed from a direction perpendicular to the main surface of the third magnetic layer.
20. The device of claim 16 , wherein a structure including the first magnetic layer, the second magnetic layer, the third magnetic layer and the nonmagnetic layer constitutes a spin-transfer-torque (STT) magnetoresistive element.