Patent ID: 7502248

Claim:
A magnetic memory comprising: first and second magnetically changeable ferromagnetic layers; a ferromagnetic reference layer having a fixed magnetization state; a first spacer layer interposed between the first and second magnetically changeable ferromagnetic layers; and a second spacer layer interposed between the ferromagnetic reference layer and the second magnetically changeable ferromagnetic layers, wherein the first spacer layer and the second spacer layer are non-magnetic, a magnetization orientation of the second magnetically changeable ferromagnetic layer is parallel or antiparallel with respect to a magnetization orientation of the ferromagnetic reference layer, and a magnetization orientation of the first magnetically changeable ferromagnetic layer is parallel or antiparallel with respect to the magnetization orientation of the second magnetically changeable ferromagnetic layer, and a difference ΔR 1 between maximum and minimum resistances of a stack comprising the second magnetically changeable ferromagnetic layer, the second spacer layer, and the ferromagnetic reference layer is different from a difference ΔR 2 between maximum and minimum resistances of a stack comprising the first magnetically changeable ferromagnetic layer, the first spacer layer, and the second magnetically changeable ferromagnetic layer.