Magnetic memory element utilizing spin transfer switching

1. A magnetic memory element utilizing spin transfer switching, comprising:

a pinned layer;

a tunneling barrier layer, disposed on the pinned layer; and

a free layer structure, comprising a composite free layer, wherein the composite free layer comprises:

a first free layer, disposed on the tunneling barrier layer and having a first spin polarization factor and a first saturation magnetization;

an insert layer, disposed on the first free layer; and

a second free layer, disposed on the insert layer and having a second spin polarization factor and a second saturation magnetization, wherein

the first spin polarization factor is larger than the second spin polarization factor, the second saturation magnetization is smaller than the first saturation magnetization, and a magnetization vector of the first free layer and a magnetization vector of the second free layer are arranged as parallel-coupled.

2. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , wherein a material of the tunneling barrier layer comprises magnesium oxide (MgO) or aluminum oxide.

3. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , wherein a material of the first free layer comprises a magnetic material.

4. The magnetic memory element utilizing spin transfer switching as claimed in claim 3 , wherein the magnetic material is a magnetic alloy of Fe, Ni, Co, and B.

5. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , wherein a material of the insert layer comprises a non-magnetic material.

6. The magnetic memory element utilizing spin transfer switching as claimed in claim 5 , wherein the non-magnetic material is Ta, Ru, Mg, Ti, Cu, Cr, Ag, Pt, Pd, Au, TaO x , RuO x , MgO or TiO x .

7. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , wherein a material of the second free layer comprises a magnetic material.

8. The magnetic memory element utilizing spin transfer switching as claimed in claim 7 , wherein the magnetic material is a magnetic alloy of Fe, Ni, Co and B.

9. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , wherein a thickness of the insert layer is a thickness sufficient to render the magnetization vector of the first free layer and the magnetization vector of the second free layer arranged as parallel-coupled.

10. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , wherein a thickness of the insert layer is 1-6 angstroms or 12-18 angstroms.

11. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , further comprising a pinning layer, wherein the pinned layer is disposed on the pinning layer.

12. The magnetic memory element utilizing spin transfer switching as claimed in claim 11 , wherein a material of the pinning layer comprises an anti-ferromagnetic material.

13. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , further comprising a capping layer disposed on the composite free layer.

14. The magnetic memory element utilizing spin transfer switching as claimed in claim 13 , wherein a material of the capping layer is Ta, Ti, Ru, AlO x or MgO.

15. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , wherein the free layer structure comprises a synthetic anti-ferromagnetic free layer.

16. The magnetic memory element utilizing spin transfer switching as claimed in claim 15 , wherein when the free layer structure is the synthetic anti-ferromagnetic free layer, the free layer structure further comprises:

a first spacer layer, disposed on the composite free layer; and

a third free layer, disposed on the first spacer layer.

17. The magnetic memory element utilizing spin transfer switching as claimed in claim 16 , wherein a material of the first spacer layer is Ru, Cr or Cu.

18. The magnetic memory element utilizing spin transfer switching as claimed in claim 16 , wherein a material of the third free layer comprises a magnetic material.

19. The magnetic memory element utilizing spin transfer switching as claimed in claim 16 , wherein the third free layer is an identical layer as the composite free layer.

20. The magnetic memory element utilizing spin transfer switching as claimed in claim 1 , further comprising a stabilized layer disposed on the free layer structure.

21. The magnetic memory element utilizing spin transfer switching as claimed in claim 20 , wherein the stabilized layer comprises an anti-ferromagnetic layer.

22. The magnetic memory element utilizing spin transfer switching as claimed in claim 21 , wherein the anti-ferromagnetic layer comprises PtMn, IrMn, FeMn.

23. The magnetic memory element utilizing spin transfer switching as claimed in claim 21 , wherein a thickness of the anti-ferromagnetic layer is within a range of 10 angstroms to 50 angstroms.

24. The magnetic memory element utilizing spin transfer switching as claimed in claim 21 , further comprising a second spacer layer disposed between the free layer structure and the anti-ferromagnetic layer.

25. The magnetic memory element utilizing spin transfer switching as claimed in claim 24 , wherein a thickness of the anti-ferromagnetic layer is greater than 50 angstroms.

26. The magnetic memory element utilizing spin transfer switching as claimed in claim 24 , wherein a material of the second spacer layer comprises a metal with a spin diffusion length greater than 100 angstroms.

27. The magnetic memory element utilizing spin transfer switching as claimed in claim 26 , wherein the metal is Ru, Ta, Ti, Cu, Au, Ag, Al, Pt or Pd.