Spin transfer magnetic element with free layers having high perpendicular anisotropy and in-plane equilibrium magnetization

Abstract

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, nonmagnetic spacer, and free layers. The spacer layer resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The free layer includes a first ferromagnetic layer and a second ferromagnetic layer. The second ferromagnetic layer has a very high perpendicular anisotropy and an out-of-plane demagnetization energy. The very high perpendicular anisotropy energy is greater than the out-of-plane demagnetization energy of the second layer.

1 . A magnetic element comprising:
 a pinned layer;   spacer layer, the spacer layer being nonmagnetic; and   a free layer having a free layer magnetization, the spacer layer residing between the pinned layer and the free layer, the free layer having a total perpendicular anisotropy energy and a total out-of-plane demagnetization energy, the total perpendicular anisotropy energy being greater than the total out-of-plane demagnetization energy;   wherein the magnetic element is configured to allow the free layer magnetization to be switched due to spin transfer when a write current is passed through the magnetic element.   
     
     
         2 . The magnetic element of  claim 1  wherein the free layer further includes:
 a first ferromagnetic layer; and 
 a second ferromagnetic layer adjoining the first ferromagnetic layer, the second ferromagnetic layer having a very high perpendicular anisotropy and an out-of-plane demagnetization energy, the very high perpendicular anisotropy energy being greater than the out-of-plane demagnetization energy. 
 
     
     
         3 . The magnetic element of  claim 2  wherein the first ferromagnetic layer has a high spin polarization. 
     
     
         4 . The magnetic element of  claim 3  wherein the first ferromagnetic layer includes at least one of Co, Fe and Co Fe. 
     
     
         5 . The magnetic element of  claim 3  wherein the first ferromagnetic layer is exchanged coupled with the second ferromagnetic layer. 
     
     
         6 . The magnetic element of  claim 2  wherein the second ferromagnetic layer has an out-of-plane magnetization. 
     
     
         7 . The magnetic element of  claim 2  wherein the first ferromagnetic layer resides between the spacer layer and the second ferromagnetic layer. 
     
     
         8 . The magnetic element of  claim 2  wherein the second ferromagnetic layer resides between the spacer layer and the first ferromagnetic layer. 
     
     
         9 . The magnetic element of  claim 1  wherein the spacer layer is an insulating barrier layer. 
     
     
         10 . The magnetic element of  claim 1  wherein the spacer layer is conductive. 
     
     
         11 . The magnetic element of  claim 1  wherein the free layer includes a free layer magnetization and wherein the pinned layer includes a pinned layer magnetization, the free layer magnetization being stable parallel or antiparallel to the pinned layer magnetization. 
     
     
         12 . The magnetic element of  claim 11  wherein the pinned layer is a synthetic antiferromagnet including a first ferromagnetic layer, a second ferromagnetic layer, and a spacer residing between the first ferromagnetic layer and the second ferromagnetic layer. 
     
     
         13 . The magnetic element of  claim 11  wherein the free layer is a synthetic antiferromagnet including a first ferromagnetic layer, a second ferromagnetic layer, and a spacer residing between the first ferromagnetic layer and the second ferromagnetic layer. 
     
     
         14 . The magnetic element of  claim 1  further comprising:
 an additional pinned layer; and 
 an additional spacer layer, the additional spacer layer residing between the additional pinned layer and the free layer. 
 
     
     
         15 . The magnetic element of  claim 14  wherein the free layer includes a free layer magnetization and wherein the pinned layer includes a pinned layer magnetization, the free layer magnetization being stable parallel or antiparallel to the pinned layer magnetization. 
     
     
         16 . The magnetic element of  claim 15  wherein the additional pinned layer includes an additional pinned layer magnetization, the free layer magnetization being stable parallel to antiparallel to the pinned layer magnetization. 
     
     
         17 . The magnetic element of  claim 14  wherein the magnetic element resides on a substrate, the pinned layer being between the substrate and the additional pinned layer. 
     
     
         18 . The magnetic element of  claim 14  wherein the magnetic element resides on a substrate, the additional pinned layer being between the substrate and the pinned layer.