Precessional spin current structure for magnetic random access memory with novel capping materials
A magnetic memory element having a magnetic free layer and a magnetic reference layer with a non-magnetic barrier layer between the magnetic reference layer and the magnetic free layer. A spin current layer (which may be a precessional spin current layer) is located adjacent to the magnetic free layer and is separated from the magnetic free layer by a non-magnetic coupling layer. A material layer adjacent to and in contact with the spin current layer, has a material composition and thickness that are chosen to provide a desired effective magnetization in the spin current layer. The material layer, which may be a capping layer or a seed layer, can be constructed of a material other than tantalum which may include one or more of Zr, Mo, Ru, Rh, Pd, Hf, W, Ir, Pt and/or alloys and/or nitrides of these elements.
1. A magnetic memory element for use in a magnetic memory array, the magnetic memory element comprising:
a magnetic tunnel junction structure including a magnetic free layer, a magnetic reference layer and a non-magnetic barrier layer located between the magnetic free layer and the magnetic reference layer;
a precessional magnetic spin current layer located adjacent to the magnetic free layer;
a coupling layer located between the precessional magnetic spin current layer and the magnetic free layer; and
a material layer in contact with the precessional magnetic spin current layer, the material layer comprising one or more of Zr, Mo, Rh, Pd, Hf, W, Ir, Pt and/or alloys and/or nitrides of these elements and containing no Ta;
wherein the coupling layer comprises Magnesium Oxide.
2. The magnetic memory element as in claim 1 , wherein the magnetic free layer and the magnetic reference layer each have a perpendicular magnetic anisotropy and the precessional magnetic spin current layer has a substantially parallel magnetic anisotropy.
3. The magnetic memory element as in claim 1 , wherein the coupling layer has a thickness of 0.3-1.5 nm.
4. A magnetic memory element for use in a magnetic memory array, the magnetic memory element comprising:
a magnetic reference layer;
a magnetic free layer;
a non-magnetic barrier layer located between the magnetic reference layer and the magnetic free layer;
a precessional magnetic spin current layer;
a coupling layer located between the precessional magnetic spin current layer and the magnetic free layer; and
a capping layer formed over and contacting the precessional magnetic spin current layer, the capping layer comprising one or more of Zr, Mo, Rh, Pd, Hf, W, Ir, Pt and/or alloys and/or nitrides of these elements and containing no Ta;
wherein the coupling layer comprises Magnesium Oxide.
5. The magnetic memory element as in claim 4 , wherein the magnetic reference layer and the magnetic free layer each have a perpendicular magnetic anisotropy and the precessional magnetic spin current layer has a substantially parallel magnetic anisotropy.
6. The magnetic memory element as in claim 4 , wherein the coupling layer has a thickness of 0.3-1.5 nm.
7. A magnetic memory element for use in a magnetic memory array, the magnetic memory element comprising:
a seed layer;
a precessional magnetic spin current layer formed on and in contact with the seed layer;
a magnetic free layer;
a non-magnetic coupling layer located between the precessional magnetic spin current layer and the magnetic free layer;
a magnetic reference layer; and
a non-magnetic barrier layer located between the magnetic reference layer and the magnetic free layer;
wherein the seed layer comprises one or more of Zr, Rh, Pd, Hf, Ir, Pt and/or alloys and/or nitrides of these elements and contains no Ta;
wherein the coupling layer comprises Magnesium Oxide.
8. The magnetic memory element as in claim 7 , wherein the magnetic free layer and magnetic reference layer each have a perpendicular magnetic anisotropy and the precessional magnetic spin current layer has a magnetic anisotropy with a primary component in a direction parallel a major surface of the magnetic free layer with the magnetic spin current layer.
9. The magnetic memory element as in claim 7 , wherein the coupling layer has a thickness of 0.3-1.5 nm.