A first-principles-based computational tool for simulating phonons of magnetic random solid
solutions including thermal magnetic fluctuations is developed. The method takes
fluctuations of force constants due to magnetic excitations as well as due to chemical
disorder into account. The developed approach correctly predicts the experimentally
observed unusual phonon hardening of a transverse acoustic mode in Fe–Pd an Fe–Pt
Invar alloys with increasing temperature. This peculiar behavior, which cannot be explained …