Domain wall jaggedness induced by the random anisotropy orientation in magneto-optic materials: A computer simulation study

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Abstract
Computer simulations of magnetic domain structure in thin films of amorphous rare‐earth transition metal magneto‐optic recording media are performed. In these simulations, the recording media are two‐dimensional lattice of 64×64 magnetic moments with a lattice distance of 10 Å. The motion of the magnetic moments follows the dynamic Landau–Lifshitz–Gilbert (LLG) equation under the influence of an effective field arising from the local anisotropy, nearnest‐neighbor exchange, classical dipole–dipole interaction, and an external applied field. Within the constraints of the LLG equation, we have investigated the process of domain wall formation for a medium with random anisotropy orientation. Even for very small randomness of anisotropy orientation, it is found that the 2π‐Bloch wall line appears at the boundaries of magnetic domains and the domain wall is jagged. Finally, the effects of exchange stiffness coefficient Ax and anisotropy coefficient Ku on the wall width and the jaggedness which measured the straightness of domain wall are studied.