Effect of lattice vibrations on magnetic phase transition in BCC Iron

Abstract

A Heisenberg model of exchange is built from first-principle calculations, with the pair-exchange parameters fitted as a function of both the interatomic distance and local environment parameters (i.e., the shell number, the atomic volume, and the local displacement). Monte Carlo simulations are performed to study the effect of lattice vibrations on the magnetic phase transition in BCC iron. It is shown that our model provides a transition temperature and specific heat coinciding with the measurements, and critical exponents consistent with those of 3D Heisenberg Universality.