Spin valve sensor having antiparallel (AP) pinned layer with high resistance and low coercivity

摘要

A spin valve sensor includes an antiparallel (AP) pinned layer that has first and second ferromagnetic layers separated by a thin coupling layer. The first ferromagnetic layer is exchange coupled to an antiferromagnetic pinning layer so that its magnetic moment is oriented in a first direction and the second ferromagnetic layer is exchange coupled to the first ferromagnetic layer with its magnetic moment oriented in a second direction that is antiparallel to the first direction. In the preferred embodiment the first ferromagnetic layer is cobalt iron niobium hafnium (CoFeNbHf) and the second ferromagnetic layer is cobalt (Co). With this arrangement the first ferromagnetic layer reduces current shunting and has a high coercivity so as to stabilize the pinning of the pinned layer. The cobalt (Co) of the second ferromagnetic layer enhances the spin valve effect by being adjacent to a nonmagnetic electrically conductive spacer layer which, in turn, is adjacent to a ferromagnetic free layer.