Predicting atomic diffusion in concentrated magnetic alloys: The case of paramagnetic Fe-Ni

Predicting atomic diffusion in concentrated magnetic systems is challenging due to thermal magnetic effects and complex magnetochemical interplay. We propose an efficient approach via kinetic Monte Carlo using ab initio parametrized models. We demonstrate its accuracy in the case of Fe-Ni alloys, where we successfully predict and explain the weak composition dependence of diffusion coefficients due to a compensation of distinct contributions of their constituents. The diffusion-behavior difference between the paramagnetic and the magnetic ground states is elucidated, evidencing the role of magnetic disorder.