Microstructure, magnetic and electronic transport properties of reactively facing-target sputtered epitaxial Mn4N films

The structure, magnetic and electronic transport properties of epitaxial Mn4N films fabricated by the facing-target reactive sputtering method have been investigated systematically. The high-quality growth of Mn4N films was confirmed by X-ray θ-2θ, pole figures and high-resolution transmission electron microscopy. The Mn4N films exhibit ferrimagnetic with strong perpendicular magnetic anisotropy. The saturation magnetization of Mn4N films decreases with increasing temperature, following the Bloch’s spin wave theory. The resistivity of Mn4N films exhibits metallic conductance mechanism. Debye temperature of Mn4N is estimated to be 85 K. The calculated residual resistivity ρxx0 of the 78.8 nm-thick Mn4N film is 30.56 μΩ cm. The magnetoresistances of Mn4N films display a negative signal and butterfly shape. The sign of anisotropic magnetoresistance (AMR) is positive, which infers that the AMR is dominated by the spin-up conduction electrons. Moreover, the transformation of fourfold to twofold symmetry for AMR and twofold to onefold symmetry for planar Hall resistivity is attributed to tetragonal crystal field effect.