Patent ID: 8385026

Claim:
A tunneling magnetoresistive (TMR) device comprising: a substrate; a pinned ferromagnetic layer having an in-plane magnetization direction; a free ferromagnetic layer having an in-plane magnetization direction substantially free to rotate in the presence of an external magnetic field; and an electrically insulating tunneling barrier layer between the pinned ferromagnetic layer and the free ferromagnetic layer; wherein the free ferromagnetic layer comprises a first ferromagnetic layer comprising an alloy of one or more of Co, Fe, Ni and B and a ferromagnetic backing layer, the first ferromagnetic layer being between the tunneling barrier layer and the backing layer and the backing layer having a thickness whereby the magnetic moment per unit area of the backing layer is less than two-thirds the total magnetic moment per unit area of the free ferromagnetic layer; and wherein the backing layer comprises a ferromagnetic material selected from the group consisting of (CO x Fe (100-x) ) (100-y) Ge y where the subscripts represent atomic percent, x is equal to or greater than 45 and less than or equal to 55, and y is equal to or greater than 5 and less than or equal to 33; (Co 2 Mn) (100-y) Ge y where the subscripts represent atomic percent, and y is equal to or greater than 25 and less than or equal to 33; (Co 2 Mn) (100-y) Si y where the subscripts represent atomic percent, and y is equal to or greater than 25 and less than or equal to 33; (Co 2 Fe x n (1-x) )Ge where x is equal to or greater than 0.2 and less than or equal to 0.5; and (Co 2 Fe x n (1-x) )Si where x is equal to or greater than 0.2 and less than or equal to 0.5.