Microstructures of a sputtered Ni56Mn27Ga17 ferromagnetic shape memory alloy thin film

Abstract A Ni 56 Mn 27 Ga 17 ferromagnetic shape memory alloy thin film was deposited onto a thermal substrate of 673 K by using radio frequency (RF) magnetron sputtering technique. The crystallographic structure and microstructures of the thin film are investigated by X-ray diffraction, transmission electron microscopy and high-resolution transmission electron microscopy, respectively. The results show the thin film is in martensitic state with a non-modulated tetragonal structure at room temperature. The martensite variants in the thin film are twinned relationship with (2 1 2) I type twin. The nanotwinned structures for non-modulated martensite variants are revealed at atomic level.