Patent ID: 7599157

Claim:
A current-perpendicular-to-the-plane spin-valve (CPP-SV) 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 pinned ferromagnetic layer having an in-plane magnetization direction; an antiparallel-coupled free ferromagnetic layer having an in-plane magnetization direction substantially free to rotate in the presence of an external magnetic field and comprising a first free ferromagnetic layer, a second free ferromagnetic layer and an antiparallel coupling (APC) layer between the first and second free layers; and an electrically conductive spacer layer between the first free ferromagnetic layer and the pinned ferromagnetic layer with the first free layer being between the spacer layer and the APC layer of said free layer; wherein at least one of the first free layer and the pinned layer comprises an amorphous ferromagnetic alloy comprising a nonmagnetic element X, wherein X is selected from the group consisting of B, Tb, Si, Ge, Nb and Mg, and at least one of Co, Ni and Fe.