Enhanced Anisotropic Magnetoresistance of Ion-Beam-Deposited Ni_(80)Fe_(20)-Ni_xFe_(1-x)O Composite Films

摘要

Composite films of Ni_(80)Fe_(20)-Ni_xFe_(1-x)O were prepared by a dual ion-beam deposition technique. Magnetoresistance (MR) was measured both at 77 and 298 K in a magnetic field applied in plane, parallel and perpendicular to the electrical current. Typical anisotropic magnetoresistance (AMR) was observed in as-deposited and annealed samples. The most interesting result is that for annealed samples, the shape of the MR curve is sharp and symmetric and the total MR ratio increases with oxygen content in the films, as compared with as-deposited samples. Furthermore, the total MR ratio reaches a maximum (～4.5 and 14% at 298 and 77 K, respectively) in films prepared with 44% oxygen in the assist beam. This enhanced AMR is attributed to the strong anisotropic scattering at interfaces between the ferromagnetic metal and oxide phases.