Monte Carlo and first-principles approaches for single crystal and polycrystalline Ni2MnGa Heusler alloys

Abstract

The magnetization behaviour of the ferromagnetic shape memory Heusler Ni2MnGa alloy under applied magnetic fields is studied using first-principles and Monte Carlo (MC) calculations. Calculations were carried out for single-crystal and polycrystalline structures with magnetic domains. In the multi-domain approach, the stochastic competition between the magnetic anisotropy field and the external magnetic field is taken into account by introducing a probability factor. By constructing a complex Hamiltonian model with ab initio input parameters, we can predict the temperature dependence of the magnetization in Heusler alloys for low and high magnetic fields by means of MC simulations. The theoretical iso-field magnetization curves are in good agreement with experimental data.