Magnetoresistance Characterization of NiFe Films With a Planar Point Contact

Magnetoresistance (MR) characterization of NiFe films was performed with a point-contact (PC) whose size was varied from several hundreds to around ten nm2by the ion milling process. Two kinds of MR origin, which were estimated to be domain wall MR (DWMR) and anisotropic MR (AMR), were observed by analytical decomposition of the R-H curves. The MRs showed contrastive dependence on the PC conductance due to difference of area in which they occurred. The DWMR in the PC increased as the PC size decreased and reached to a maximum of about 12.5%. The DWMR dependence on the NiFe-PC size coincided with that of fitting approximation based on some previous reports