Large-scale computer simulations of magneto-optical thin films with nanoscale structures are performed on the Connection Machine. The magneto-optical thin films are modeled by a two-dimensional lattice of magnetic dipoles which follow the Landau-Lifshitz-Gilbert dynamic equation. The effective field on each dipole includes the local anisotropy, the nearest neighbor exchange interactions, the magnetic dipole-dipole interactions, and an externally applied field. The film is divided into many patches (regions) and each patch can have different properties. Four different patchy films are studied. (i) The film has different exchange stiffness constant on the patch borders. (ii) The film has large magnetization, but has zero exchange on the patch borders. (iii) The patches have different easy axis orientations. (iv) The patches have different anisotropy constants. The computer simulations show that films with different kinds of patches have different features in their magnetic behavior. Based on these correspondences between the nanostructure and the magnetic properties, certain features recently observed in several magneto-optical thin films are able to be explained.
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