Modeling two-dimensional magnetic domain patterns

Abstract

Two-dimensional magnetic garnets exhibit complex and fascinating magnetic domain structures, like stripes, labyrinths, cells, and mixed states of stripes and cells. These patterns do change in a reversible way when the intensity of an externally applied magnetic field is varied. The main objective of this contribution is to present the results of a model that yields a rich pattern structure that closely resembles what is observed experimentally. Our model is a generalized two-dimensional Ising-like spin-1 Hamiltonian with long-range interactions, which also incorporates anisotropy and Zeeman terms. The model is studied numerically by means of Monte Carlo simulations. Changing the model parameters, stripes, labyrinth, and/or cellular domain structures are generated. For a variety of cases we display the patterns and determine the average size of the domains, the ordering transition temperature, specific heat, magnetic susceptibility, and hysteresis cycle. Finally, we examine the reversibility of the pattern evolution under variations of the applied magnetic field. The results we obtain are in good qualitative agreement with experiment