Magnetic tunnel junction device and magnetic resistance memory device

1. A magnetic tunnel junction device comprising:

a free layer configured to have a first magnetization direction that is changeable;

a pinned layer that is configured to maintain a second magnetization direction in a predetermined direction; and

an insulating layer between the free layer and the pinned layer,

wherein the free layer comprises a first free layer and a second free layer that is antiferromagnetic-coupled to the first free layer, and

wherein the first free layer has a perpendicular magnetic anisotropy and a high polarizability relative to the second free layer.

2. The magnetic tunnel junction device of claim 1 ,

wherein the first free layer is between the insulating layer and the second free layer, and

wherein a magnetic anisotropy of the second free layer is less than a magnetic anisotropy of the first free layer.

3. The magnetic tunnel junction device of claim 2 , further comprising:

an antiferromagnetic coupling (AFC) control layer configured to control antiferromagnetic coupling between the first free layer and the second free layer.

4. The magnetic tunnel junction device of claim 1 ,

wherein the first free layer is between the insulating layer and the second free layer, and

wherein the second free layer comprises a second thickness that is less than a first thickness of the first free layer.

5. The magnetic tunnel junction device of claim 4 , further comprising:

an antiferromagnetic coupling (AFC) control layer configured to control antiferromagnetic coupling between the first free layer and the second free layer.

6. The magnetic tunnel junction device of claim 1 ,

wherein the first free layer is between the insulating layer and the second free layer, and

wherein the first free layer comprises a first thickness that is less than a second thickness of the second free layer.

7. The magnetic tunnel junction device of claim 6 , further comprising:

an antiferromagnetic coupling (AFC) control layer configured to control antiferromagnetic coupling between the first free layer and the second free layer.

8. The magnetic tunnel junction device of claim 1 , further comprising:

an antiferromagnetic coupling (AFC) control layer configured to control antiferromagnetic coupling between the first free layer and the second free layer.

9. The magnetic tunnel junction device of claim 8 , wherein the AFC control layer comprises a magnetic layer having a thickness less than or equal to 2 nm.

10. The magnetic tunnel junction device of claim 8 , wherein the AFC control layer comprises at least one of MnGa, Ru, Ir, MgO, Pt, Co, Pd, W, or Ta.

11. A magnetic resistance memory device comprising:

a magnetic tunnel junction device comprising:

a free layer configured to have a first magnetization direction that is changeable;

a pinned layer that is configured to maintain a second magnetization direction in a predetermined direction; and

an insulating layer between the free layer and the pinned layer; and

an electrode configured to receive a voltage to apply to the magnetic tunnel junction device,

wherein the free layer comprises a first free layer and a second free layer that is antiferromagnetic-coupled to the first free layer, and

wherein the first free layer has a perpendicular magnetic anisotropy and a high polarizability relative to the second free layer.

12. The magnetic resistance memory device of claim 11 ,

wherein the electrode is configured to apply the voltage to the magnetic tunnel junction device changes the first magnetization direction of the free layer.

13. The magnetic resistance memory device of claim 11 ,

wherein the voltage is applied in a direction substantially perpendicular to junction surfaces of the pinned layer and the free layer such that a current flows through the magnetic tunnel junction device by a tunneling effect.

14. The magnetic resistance memory device of claim 11 ,

wherein a value of data written in the magnetic resistance memory device is changed by changing a current direction through the free layer.

15. The magnetic resistance memory device of claim 11 ,

wherein the electrode is configured to apply the voltage between a bit line and a diffusion region of the magnetic resistance memory device.

16. The magnetic resistance memory device of claim 11 , further comprising:

an antiferromagnetic coupling (AFC) control layer between the first free layer and the second free layer,

wherein the AFC control layer is configured to control antiferromagnetic coupling between the first free layer and the second free layer.

17. A memory cell of a magnetic resistance memory device, the memory cell comprising:

a magnetic tunnel junction device,

wherein the magnetic tunnel junction device comprises a first layer with high spin polarization and a second layer with perpendicular magnetization relative to the first layer.

18. The memory cell of claim 17 ,

wherein the memory cell is configured to receive a voltage applied to the magnetic tunnel junction device between a bit line and a first diffusion region of the memory cell.

19. The memory cell of claim 17 , further comprising:

an antiferromagnetic coupling (AFC) control layer configured to control antiferromagnetic coupling between the first layer and the second layer.

20. The memory cell of claim 17 , further comprising:

a substrate;

a first diffusion region on the substrate, wherein the first diffusion region comprises a drain region;

a second diffusion region comprising a source region;

a contact plug that electrically connects the first diffusion region and the magnetic tunnel junction device; and

a bit line connected to the magnetic tunnel junction device and configured to select the memory cell,

wherein the memory cell is configured to receive a voltage applied to the magnetic tunnel junction device between the bit line and the first diffusion region.