Patent ID: 7106561

Claim:
A magnetoresistive sensor capable of sensing external magnetic fields when a sense current is applied perpendicular to the planes of the layers in the sensor, the sensor comprising: a substrate; a free ferromagnetic layer having an in-plane magnetization direction oriented substantially in a first direction 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; a pinned ferromagnetic layer having an in-plane magnetization direction oriented in a second direction substantially orthogonal to said first direction; a first antiferromagnetic layer exchange-coupled to the pinned layer and preventing substantial rotation of the magnetization direction of the pinned layer in the presence of an external magnetic field in the range of interest; a nonmagnetic spacer layer between the free and pinned layers; an antiparallel-pinned ferromagnetic biasing layer magnetically-coupled to the free layer and having a net in-plane magnetization direction oriented substantially orthogonal to said first direction in the absence of an external magnetic field, the biasing layer comprising a first ferromagnetic film, a second ferromagnetic film and an antiferromagnetically-coupling spacer film between said first and second ferromagnetic films; a second antiferromagnetic layer exchange-coupled with one of said first and second ferromagnetic films of the biasing layer for substantially preventing rotation of the net magnetization direction of the biasing layer in the presence of an external magnetic field in the range of interest; and an electrically-conducting spacer layer between the biasing and free layers, the spacer layer between the biasing and free layers inducing substantial orthogonal magnetic coupling of the free layer to the biasing layer.