CPP-GMR of spin valves with CoxFe1−x alloy

Spin valves with free and pinned layers constructed from Co50Fe50 exhibit higher current-perpendicular-to-plane (CPP) giant-magnetoresistance (GMR) than the conventional Co90Fe10 alloy. In order to investigate this enhancement mechanism, we measured CPP-GMR and the crystalline structure of spin valves with Co90Fe10, Co70Fe30, Co50Fe50 and Co20Fe80 for pinned and free layers. The spin valves with Co50Fe50 and Co20Fe80 show the same CPP-GMR and these are higher than those with Co90Fe10 and Co70Fe30. These results do not agree with the report about the Fe-Ni and Co-Ni systems that calculated that concludes that the stoichiometric concentration has the highest CPP-GMR. In the Co-Fe system, the crystalline structure and the strain also contribute to CPP-GMR.