Vibrational and magnetic contribution to entropy of an L1 < inf > 2 < /inf > ordered and a partially ordered Ni < inf > 3 < /inf > Mn alloy: Results from thermal expansion measurements and model calculations

Abstract

Thermal expansion measurements have been performed on an L12 ordered and a quenched Ni3Mn alloy and the role of electrons, phonons and magnetic moments on their thermodynamic properties has been studied using theoretical models. We show that with increasing atomic disorder the itinerant nature of the electron moments decreases. We furthermore show that magnetic interactions do not influence the chemical ordering of Ni3Mn, while lattice vibrations play an important role in its ordering transition.