Patent ID: 7057862

Claim:
A magnetoresistive sensor comprising a stack of layers and capable of sensing external magnetic fields when a sense current is applied perpendicular to the planes of the layers in the stack, the stack of layers including: a first nonmagnetic spacer layer; a second nonmagnetic spacer layer; a free ferromagnetic layer between the first and second spacer layers and having a magnetization direction oriented substantially longitudinally along the length of the layer in the absence of an external magnetic field, said free layer magnetization direction being substantially free to rotate in the presence of an external magnetic field in the range of interest; a pinned ferromagnetic layer adjacent the first spacer layer and having a magnetization direction oriented in a preferred direction; a first antiferromagnetic layer exchange coupled to the pinned layer and preventing substantial rotation of the magnetization of the pinned layer in the presence of an external magnetic field in the range of interest; a ferromagnetic stabilizing layer adjacent the second spacer layer; and a second antiferromagnetic layer exchange coupled to the stabilizing layer, the second antiferromagnetic layer having a blocking temperature less than the blocking temperature of the first antiferromagnetic layer, the stabilizing layer and the free layer having nonlongitudinally-oriented magnetic domains magnetically-coupled across the second spacer layer in the absence of an external magnetic field and the absence of a sense current.