Resettable dual AP pinned valve sensor insensitive to sense current direction and having symmetrically balanced fields about a free layer

摘要

A dual spin valve sensor is provided which includes a ferromagnetic free layer, first and second antiparallel (AP) pinned layer structures, a nonmagnetic conductive first spacer layer between the free layer and the first AP pinned layer structure, a nonmagnetic conductive second spacer layer between the free layer and the second AP pinned layer structure, an antiferromagnetic first pinning layer exchange coupled to the first AP pinned layer structure for pinning a magnetic moment of the first AP pinned layer structure in a first direction and an antiferromagnetic second pinning layer exchange coupled to the second AP pinned layer for pinning a magnetic moment of the second AP pinned layer structure in a second direction. The first and second AP pinned layer structures have thicknesses which urge the magnetic moment of the first AP pinned layer structure in the first direction and urge the magnetic moment of the second AP pinned layer in the second direction when a current pulse is conducted through the spin valve sensor.