Patent ID: 7554775

Claim:
A bottom-type giant magnetoresistance (GMR) sensor comprising: a nonmagnetic Al—O first seed layer; a nonmagnetic Ni—Cr—Fe second seed layer deposited on the first seed layer; a ferromagnetic Ni—Fe third seed layer deposited on the second seed layer; an antiferromagnetic Ir—Mn—Cr pinning layer deposited on the third seed layer; a ferromagnetic Co—Fe first pinned layer deposited on the pinning layer; a nonmagnetic Ru antiparallel (AP) spacer layer deposited on the first pinned layer; a ferromagnetic Co—Fe second pinned layer deposited on the AP spacer layer; a nonmagnetic Cu—O GMR spacer layer deposited on the second pinned layer; a first free layer of ferromagnetic Co—Fe deposited on the GMR spacer layer; a second free layer of ferromagnetic Ni—Fe deposited on the first free layer; and a nonmagnetic Ta cap layer deposited above the first and second free layers; wherein the first pinned layer comprises first and second Co—Fe films, the first Co—Fe film contacting the antiferromagnetic pinning layer and having an Fe content of approximately from 20 to 80 atomic percent, and the second Co—Fe film contacting the AP spacer layer and having an Fe content of approximately from 0 to 10 atomic percent.