Phase transformations in sputter deposited NiMn thin films

The phase changes of NiMn films, produced by co-sputtering from elemental targets on glass slides, were investigated using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The as-deposited NiMn thin films were found to be amorphous or nanocrystalline with a high defect density. When subjected to thermal annealing, the films exhibit four exothermic reactions as measured by DSC. The second and the third peaks were attributed to the formation of the fcc (A1) phase and the face-centered tetragonal (L10) phase, respectively. The first peak around 160 °C and last one at 440 °C could be due to oxidation and coarsening, respectively.