材料期刊网

We simulate by the Monte Carlo method the dynamic hysteresis and hysteresis scaling of two-dimensional uniaxially anisotropic Heisenberg model submitted to a time-oscillating magnetic field h of frequency f and amplitude h(0). It is revealed that the hysteresis area as a function of f and h(0) exhibits well-defined power law behaviors over the low-f and high-f regimes as long as h(0) is high enough. The power law exponents for the low-f regime depend on the uniaxially anisotropic factor K, but the exponents for the high-f regime are universal. The single-peaked hysteresis dispersions at different h(0) follow both the empirical scaling approach and the single-variable scaling hypothesis, respectively, demonstrating the existence of a single characteristic time for spin reversal mode given the amplitude h(0). However, the scaling may be broken when h(0) is low, due to the coexistence of spin reversal and spin tilting resonances. (c) 2007 American Institute of Physics.