The number of Cu lamination effect on current-perpendicular-to-plane giant-magnetoresistance of spin valves with Fe ₅₀Co ₅₀ alloy

The current-perpendicular-to-plane (CPP) giant-magnetoresistance (GMR) of spin valves with Fe50 Co50 alloy was investigated. It has been reported that the Cu inserted in Fe50 Co50 is effective for enhancing CPP-GMR. In this paper, we investigated the number of Cu lamination effect on CPP-GMR and clarified that higher CPP-GMR is obtained by decreasing the number of Cu layers. In order to ascertain the reason for this tendency, the crystalline structure and magnetization were examined. As a result, it was found that the d spacing of Fe50 Co50 increases when the number of Cu layers is increased, although saturation magnetization does not change.