Study on Structure, Magnetic Properties and Transport Properties of Hexagonal MnNiGa Films
Keywords: hexagonal structure, MnNiGa, magnetron sputtering, perpendicular magnetic anisotropy, spintronics
Hexagonal structure MM'X material is a kind of potential new magnetic phase change functional material, which has received great attention in recent years. In this paper, the crystal structure, magnetic properties and transport properties of ternary alloy MnNiGa films at different sputtering temperatures were systematically investigated by DC magnetron sputtering and first-principles calculations. X-ray diffraction analysis showed that the MnNiGa film was a hexagonal structure having a Ni2In type (space group P63/mmc). Scanning electron microscopy revealed the effect of sputtering temperature on the surface morphology of the film, while the energy spectrum analysis showed that the composition of the film hardly changed with temperature. Magnetic properties show that the films are ferromagnetic and have magnetic anisotropy. Magnetoresistance (MR) and Hall resistance were measured at the same time. The results show that MR is negative and linear with the magnetic field. The anomalous Hall effect (AHE) plays a dominant role in the Hall effect, and AHE is mainly caused by the oblique scattering mechanism. The energy band calculation results show that the spin polarization of the MnNiGa bulk is 33%, whereas in the G-A direction, the spin polarization is as high as 100%. This indicates that the hexagonal structure MnNiGa is likely to be a candidate for spintronic materials.