Study on electronic transport and magnetic properties for antiperovskite Mn ₃CuN _x thin films fabricated with different N ₂ flow rates

The antiperovskite Mn ₃CuN _x thin films are successfully deposited on single crystal Si (100) substrates using facing target magnetron sputtering. The effects of nitrogen content on the structures and physical properties of the Mn ₃CuN _x thin films are investigated. The crystal structure, composition, surface morphology and the temperature dependence of resistivity and magnetization are characterized by X-ray diffraction, Auger electron spectroscopy, atomic force microscope, X-ray photoelectron spectroscopy, physical property measurement systems and superconducting quantum interference device. It is found that the thin film has an antiperovskite structure and a preferred orientation along (200) plane. The surface roughness and particle size increase with N content increasing. N content has little influence on the electronic transport behavior of the film. All the films display semiconductor-like behaviors, i.e. their resistivities monotonically decrease considerably, which is different from the bulk counterpart. The film undergoes a magnetic transition from ferrimagnetic to paramagnetic with the increase of temperature. Moreover, the Curie temperature (T _C) increases as the N content decreases, owing to the effect of N deficiency on the interaction of Mn ₆N octahedron.