Perpendicular magnetic memory with reduced switching current

1. An apparatus comprising:

a substrate;

a magnetic tunnel junction (MTJ) comprising a fixed layer and first and second free layers between the fixed layer and the substrate;

a seed layer directly contacting the second free layer; and

a barrier layer between the first and second free layers;

wherein (a) the first free layer is non-epitaxial and includes Cobalt (Co), Iron (Fe), and Boron (B), and (b) the second free layer is an epitaxial crystal structure and includes Manganese (Mn) and Gallium (Ga).

2. The apparatus of claim 1 , wherein the barrier layer includes at least one of Tantalum (Ta), Tungsten (W), Molybdenum (Mo), Hafnium (Hf), Vanadium (V), Zirconium (Zr), Chromium (Cr), or combinations thereof and the barrier layer directly contacts both of the first and second free layers.

3. The apparatus of claim 2 comprising a dielectric layer directly contacting a top surface of the first free layer, wherein the bottom surface of the first free layer directly contacts the barrier layer.

4. The apparatus of claim 3 , wherein the fixed layer includes a sublayer comprising Co and another sublayer comprising Platinum (Pt).

5. The apparatus of claim 4 , comprising a bottom electrode between the second free layer and the substrate.

6. The apparatus of claim 5 comprising a cap layer, wherein the fixed layer is between the cap layer and the dielectric layer.

7. The apparatus of claim 6 comprising an additional fixed layer that includes Co, Fe, and B, wherein the additional fixed layer is between the fixed layer and the dielectric layer.

8. The apparatus of claim 7 comprising an additional barrier layer between the fixed layer and the additional fixed layer.

9. The apparatus of claim 2 , wherein the second free layer includes Ruthenium (Ru).

10. The apparatus of claim 2 , wherein the second free layer includes an alloy that further includes the Mn and the Ga.

11. The apparatus of claim 1 , wherein (a) the first free layer includes a thickness from a top surface of the first free layer to a bottom surface of the first free layer, and (b) the MTJ is a perpendicular MTJ based on the thickness.

12. The apparatus of claim 1 , wherein the seed layer includes at least one of Titanium (Ti), Nitrogen (N), Chromium (Cr), Ruthenium (Ru), or combinations thereof.

13. An apparatus comprising:

a substrate;

a magnetic tunnel junction comprising a fixed layer and first and second free layers; and

a seed layer directly contacting the second free layer, but not directly contacting the first free layer;

wherein

(a) the first free layer includes Cobalt (Co), Iron (Fe), and Boron (B), and

(b) the second free layer includes Manganese (Mn) and Gallium (Ga);

wherein the first and second free layers are between the fixed layer and the substrate;

wherein the seed layer includes at least one of Titanium (Ti), Nitrogen (N), Chromium (Cr), Ruthenium (Ru), or combinations thereof.

14. The apparatus of claim 13 comprising a barrier layer between the first and second free layers, wherein the barrier layer includes Tantalum (Ta).

15. The apparatus of claim 14 comprising a dielectric layer directly contacting a top surface of the first free layer, wherein the bottom surface of the first free layer directly contacts the barrier layer.

16. The apparatus of claim 13 , comprising a bottom electrode between the second free layer and the substrate, wherein the fixed layer includes Co and Platinum (Pt).

17. The apparatus of claim 16 comprising an additional fixed layer that includes Co, Fe, and B, wherein the additional fixed layer is between the fixed layer and the dielectric layer.

18. The apparatus of claim 17 comprising an additional barrier layer between the fixed layer and the additional fixed layer.