Pressure dependence of the Curie temperature in Ni2MnSn Heusler alloy: A first-principles study

Abstract

The pressure dependence of electronic structure, exchange interactions, and Curie temperature in the ferromagnetic Heusler alloy Ni2MnSn has been studied theoretically within the framework of the density-functional theory. The calculation of the exchange parameters is based on the frozen-magnon approach. The Curie temperature Tc is calculated within the mean-field approximation by solving the matrix equation for a multisublattice system. In agrement with experiment the Curie temperature increased from 362 K at ambient pressure to 396 K at 12 GPa. Extending the variation of the lattice parameter beyond the range studied experimentally, we obtained nonmonotonic pressure dependence of the Curie temperature and metamagnetic transition. We relate the theoretical dependence of Tc on the lattice constant to the corresponding dependence predicted by the empirical interaction curve. The Mn-Ni atomic interchange observed experimentally is simulated to study its influence on the Curie temperature. © 2005 The American Physical Society.