Patent ID: 7211874

Claim:
A thermally stable MTJ MRAM cell with a free layer locking mechanism comprising: a horizontal word line extending in a first direction; a horizontal, composite bit line, vertically separated from said word line, said bit line extending in a direction orthogonal to said first direction and said bit line including a first horizontally extending layer of non-magnetic high conductivity material, said layer being bounded by lateral edges and said layer having a horizontal surface proximal to said word line and a substantially identical parallel horizontal surface distal to said word line and on said horizontal surface distal to said word line and only between said lateral edges thereof, there is formed an adjacent soft magnetic layer (SAL); a multilayered magnetic tunnel junction (MTJ) element formed between said word line and said bit line, said element including a magnetically free layer having a magnetic anisotropy produced by a shape asymmetry or an anneal produced crystalline anisotropy, wherein said free layer is proximate to said SAL and has two switching states of greater and lesser stability, said states being the result of said shape asymmetric or crystalline magnetic anisotropy combined with an interaction magnetic anisotropy produced by a magnetostatic coupling of said free layer to said SAL.