Patent ID: 8497559

Claim:
A spin transfer MTJ MRAM cell comprising: an MTJ cell including a non-magnetic tunneling barrier layer formed between a magnetically pinned layer having a fixed magnetization and a magnetically free layer having a switchable magnetization; wherein said free layer has a shape anisotropy in a plane of said free layer and; wherein said free layer is surrounded by material; wherein said free layer is under a tensile or compressive stress in the plane of said free layer produced substantially by residual tensile or compressive stresses caused by differential expansion and contraction of said surrounding material and; wherein said free layer is formed having a material composition and structure that can be varied during said formation and wherein said free layer has a coefficient of magnetostriction, λ that depends upon said free layer material composition and structure, whereby, upon the exertion of said stresses said free layer acquires a total in-plane magnetic anisotropy, H ktotal , that may include a shape induced magnetic anisotropy, but is most predominantly an anisotropy due to stress and magnetostriction and whereby said MTJ cell acquires, thereby, an in-plane switching field, H s , that has a component resulting from said shape induced anisotropy and a component resulting from said stress induced anisotropy whereby a perpendicularly directed critical current is able to switch the direction of magnetization of said free layer, but the magnitude of the switching field maintains the resulting magnetization of said free layer constant and free from variations caused by thermal agitation in the absence of said critical current.