Composition dependent phase transformation of Pt0.5−xMn0.5+x from A1 to L10 phase

Pt0.5−x Mn0.5+x films were prepared by sputtering deposition of Pt foil and Mn target to study the order-disorder transition from a thermodynamic metastable fcc (A1) phase to L10 phase. Both Differential Scanning Calorimetry and High Temperature X-Ray Diffraction studies showed the phase transformation from fcc to the L10 structure for the Pt0.50Mn0.50 and Pt0.40Mn0.60 samples but along completely different kinetic paths. A composition dependent phase transformation was observed by comprehensive Differential Scanning Calorimetry studies on a series of Pt0.5−x Mn0.5+x samples. The changes of the lattice parameter and the cell volume of L10 Pt0.5−x Mn0.5+x as a function of composition suggest that the anti-site is not the dominant point defect for L10 Pt0.5−x Mn0.5+x .