Dynamic symmetry loss of high-frequency hysteresis loops in single-domain particles with uniaxial anisotropy

► We study the dynamic symmetry loss in hysteresis loops of single-domain particles. ► To account for thermal fluctuations we used the Stochastic Landau-Lifshitz method. ► The simulations cover a broad range of temperatures and frequencies. ► New phenomena is observed bellow the ferromagnetic temperature. ► Our detailed analysis show that this corresponds to a first-order phase transition.