Patent ID: 7329935

Claim:
A magnetoresistive random access device having an array of memory elements, each memory element comprising: a fixed magnetic portion, a tunnel barrier portion disposed proximate to said fixed magnetic portion; and a free SAF structure disposed proximate to said tunnel barrier portion, wherein: the array of memory elements has a finite magnetic field programming window H win represented by the equation H win ≈( Hsat − σ sat )−( Hsw + σ sw ); Hsw is a mean switching field for said array; Hsat is a mean saturation field for said array; Hsw for said each memory element is represented by the equation H SW ≅√{square root over (H k H SAT )}, wherein H k represents a total anisotropy field of said free SAF structure of said each memory element and H SAT represents a total anti-ferromagnetic coupling saturation field for said free SAF structure of said each memory element; N is an integer greater than or equal to 1; σ sw is a standard deviation for Hsw ; and σ sat is a standard deviation for H SAT , and wherein said free SAF structure is configured to have H k , H SAT , and N values such that the array of memory elements is thermally stable and requires current to operate that is below a predetermined current value.