US Patent 7773408 Nonvolatile memory device

Ferromagnetic layers have magnetizations oriented to such directions as to cancel each other, so that the net magnetization of the ferromagnetic layers is substantially zero. That is, the ferromagnetic layers are exchange-coupled with a nonmagnetic layer interposed therebetween, thereby forming an SAF structure. Since the net magnetization of the ferromagnetic layers forming the SAF structure is substantially zero, the magnetization of a recording layer is determined by the magnetization of a ferromagnetic layer. Therefore, the ferromagnetic layer is made of a CoFeB alloy having high uniaxial magnetic anisotropy, and the ferromagnetic layers are made of a CoFe alloy having a high exchange-coupling force.