Structure and properties of ternary manganese nitride Mn3CuNy thin films fabricated by facing target magnetron sputtering

Deposition of Mn3CuNy thin films on single crystal Si (1 0 0) at various substrate temperatures (Tsub) by facing target magnetron sputtering is reported. The crystal structure and composition were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results confirmed that the crystalline antiperovskite Mn3CuNy thin film with (2 0 0) highly preferred texture had been obtained at Tsub = 180 °C. Furthermore, for the resulting Mn3CuNy thin film, it showed different properties compared with the bulk counterpart. There was a paramagnetic to ferrimagnetic transition at 225 K with decreasing temperature. The change of the lattice constant with temperature presented positive thermal expansion behavior and no structural transition was observed. The average linear thermal expansion coefficient (α) is 2.49 × 10−5 K−1 from 123 K to 298 K. More interestingly, the temperature dependence of resistivity displayed a semiconductor-like behavior, i.e. an obvious monotonous decrease of resistivity with increasing temperature.

This figure reveals the dependence of the texture coefficient TC(1 1 1) and TC(2 0 0) of the Mn3CuNy thin films on Tsub. These results indicate that the preferred orientation of the Mn3CuNy thin films dramatically changed from (1 1 1) to (2 0 0) with the increase of Tsub. In one word, the orientation of Mn3CuNy thin film can be tailored by adjusting the magnetron sputtering processing parameters and substrate.It is the first time to report the deposition of Mn3CuNy thin films on single crystal Si (1 0 0) at various substrate temperatures (Tsub) by facing target magnetron sputtering. The influences of substrate temperature on crystal structure and morphology are discussed. The temperature dependences of magnetization, lattice parameters and resistivity for the resulting film are systematically investigated, which shows several different physical properties from those of previous work.Figure optionsDownload as PowerPoint slideHighlights
► Variation of the substrate temperatures adjusted the preferred orientation from (1 1 1) to (2 0 0) of the Mn3CuNy thin films.
► There exists a magnetic ordering transition at 225 K from paramagnetic (PM) to ferrimagnetic (FI), which is different than previous results.
► It shows a positive thermal expansion behavior with average linear thermal expansion coefficient 2.49 × 10−5 K−1. However there was no crystal phase transition occurred around the magnetic transition in the film.
► The temperature dependence of resistivity displayed a semiconductor-like behavior, which is quite different from the bulk sample.
► We believe that our findings may provide an important role to further utilize the potential of antiperovskite manganese nitride film.