Structure, magnetic and electronic transport properties in antiperovskite cubic γ′-CuFe3N polycrystalline films

Abstract

The structure, magnetic and electronic transport properties of the facing-target reactively sputtered polycrystalline CuFe3N films have been investigated systematically. The CuFe3N film has a cubic antiperovskite structure. The saturation magnetization satisfied the modified Bloch's spin wave theory. At 300 K, the saturation magnetization of the 80 nm-thick CuFe3N films is 402 emu/cm3, which is smaller than 800 emu/cm3 of the 80 nm-thick polycrystalline Fe4N films. The CuFe3N films are metallic. The anomalous Hall effect in the “dirty region” of σxx < 104 S/cm can be explained by the intrinsic mechanism and the side jump in the proper scaling, which is similar to Fe4N. However, the sign of magnetoresistances in CuFe3N is opposite to that of Fe4N below 20 K because the doped-Cu affects the competition among the Lorentz force, spin-orbit coupling, weak localization and s-d exchange interaction. The small anisotropic magnetoresistance is dominated by the spin-down conduction electron. The transformation from the two-fold to one-fold symmetry in the planar Hall resistivity of the 10-nm-thick-CuFe3N films is related to the competition between the temperature-dependent charge scattering and magnetic-field-dependent spin scattering.