Patent ID: 7511926

Claim:
A current perpendicular to plane (CPP) giant magnetoresistive (GMR) sensor, comprising: a first pinned layer structure; a second pinned layer structure; a third pinned layer structure, the second pinned layer structure being disposed between the first and third pinned layer structures; a first free layer structure disposed between the first and second pinned layer structures; a second free layer disposed between the second and third pinned layer structures; a first non-magnetic, electrically conductive spacer layer separating the first pinned layer structure from the first free layer structure; a second non-magnetic, electrically conductive spacer layer separating the first free layer structure from the second pinned layer structure; a third non-magnetic, electrically conductive spacer layer separating the second pinned layer structure from the second free layer; and a fourth non-magnetic spacer layer separating the second free layer from the third pinned layer structure; the second pinned layer structure consisting of: a first magnetic layer a second magnetic layer; a third magnetic layer; a first non-magnetic antiparallel coupling layer disposed between the first and second magnetic layers; and a second non-magnetic antiparallel coupling layer disposed between the second and third magnetic layers.