Magnetic memory device

1. A magnetic memory device comprising:

a first magnetization layer;

a tunnel barrier disposed on the first magnetization layer;

a second magnetization layer on the tunnel barrier; and

a spin current assisting layer on at least a portion of a top surface of the second magnetization layer and on at least a portion of a sidewall of the second magnetization layer.

2. The device of claim 1 , wherein the spin current assisting layer surrounds the sidewall of the second magnetization layer.

3. The device of claim 1 , wherein the spin current assisting layer is in contact with a portion of the tunnel barrier.

4. The device of claim 1 , further comprising a passivation layer configured to surround a sidewall of the spin current assisting layer.

5. The device of claim 1 , wherein the spin current assisting layer includes a material having a giant spin Hall effect.

6. The device of claim 1 , wherein the spin current assisting layer has a spin Hall angle of about 0.05 to about 0.5.

7. The device of claim 1 , wherein the spin current assisting layer includes at least one element selected from the group consisting of tantalum (Ta), tungsten (W), platinum (Pt), tantalum nitride (TaN x ), and tungsten nitride (WN x ).

8. The device of claim 1 , wherein the spin current assisting layer includes a first material layer formed on the sidewall of the second magnetization layer, and a second material layer disposed on the first material layer.

9. A magnetic memory device comprising:

a pinned layer including a first magnetization layer;

a free layer including a second magnetization layer;

a tunnel barrier interposed between the pinned layer and the free layer; and

a spin current assisting layer on at least a portion of a top surface of the free layer and on at least a portion of a sidewall of the free layer, wherein the spin current assisting layer is in contact with at least a portion of the tunnel barrier.

10. The device of claim 9 , wherein the magnetization easy axis extends along the sidewall of the free layer in a direction from the pinned layer toward the free layer.

11. The device of claim 9 , wherein the spin current assisting layer is not electrically connected to the pinned layer.

12. The device of claim 9 , wherein the free layer has a first width in a direction parallel to a top surface of the tunnel barrier, and

the first width of the free layer ranges from about 5 nm to about 50 nm.

13. The device of claim 12 , wherein the free layer has a first height in a direction perpendicular to the top surface of the tunnel barrier, and

the first height of the free layer ranges from about 2 nm to about 50 nm.

14. The device of claim 13 , wherein when an aspect ratio of the free layer is defined by a ratio of the first height to the first width, the aspect ratio of the free layer ranges from about 0.1 to about 25.

15. A magnetic memory device comprising:

a magnetic tunnel junction (MTJ) structure including a first magnetization layer, a second magnetization layer, and a tunnel barrier interposed between the first and second magnetization layers; and

a spin current assisting layer on at least a portion of a top surface of the MTJ structure and on a portion of a sidewall of the MTJ structure.

16. The device of claim 15 , wherein the spin current assisting layer is formed on a sidewall of the first magnetization layer.

17. The device of claim 15 , wherein the spin current assisting layer is electrically connected to the first magnetization layer.

18. The device of claim 15 , further comprising a passivation layer on the spin current assisting layer.

19. The device of claim 15 , wherein the spin current assisting layer includes a first material layer and a second material layer sequentially stacked on a sidewall of the first magnetization layer.