Blume-Capel ferromagnet driven by propagating and standing magnetic field wave: Dynamical modes and nonequilibrium phase transition

摘要

The dynamical responses of Blume-Capel (S=1) ferromagnet to the planepropagating (with fixed frequency and wavelength) and standing magnetic fieldwaves are studied sepa- rately in two dimensions by extensive Monte Carlosimulation. Depending on the values of temperature, amplitude of thepropagating magnetic field and the strength of anisotropy, two differentdynamical phases are observed. For a fixed value of anisotropy and theamplitude of the propagating magnetic field, the system undergoes a dynamicalphase transition from a driven spin wave propagating phase to a pinned or spinfrozen state as the system is cooled down. The time averaged magnetisation overa full cycle of the propagating magnetic field plays the role of the dynamicorder parameter. A comprehensive phase diagram is plotted in the plane formedby the amplitude of the propagating wave and the temperature of the system. Itis found that the phase boundary shrinks inward as the anisotropy increases.The phase boundary, in the plane described by the strength of the anisotropyand temperature, is also drawn. This phase boundary was observed to shrinkinward as the field amplitude increases.