Structure and thermomagnetic properties of polycrystalline Ni–Mn–Ga thin films

The structure and thermomagnetic properties of pulsed laser deposited polycrystalline Ni–Mn–Ga alloy films, grown onto thermally oxidized Si(100) wafers, have been investigated. The 300-nm-thick films were deposited at substrate temperatures between 500 and 600 °C from targets made from slices of a Ni2MnGa single crystal. The trends in the average composition suggest that samples deposited around 500 °C are composed of the Ni2MnGa (L21) phase as well as a nonmagnetic B2 phase. On increasing the temperature of the substrate, the Mn content as well as the saturation magnetization increase suggesting the appearance of a different magnetic phase that is tentatively ascribed to the Ni3(MnGa) (L11) magnetic phase.