Large scale micromagnetic calculations for finite and infinite 3Dferromagnetic systems using FFT

Abstract An algorithm for the solution of three-dimensional Micromagnetic problems is presented. This algorithm is based onthe evaluation of the stray field in the reciprocal space. This has been achieved by first Fourier transforming the adequate Magnetostatic field propagator and the magnetization configuration and then evaluating the product of both transforms. Thus, the stray field can be calculated as the reverse Fourier transform of this product. A very stable descent method taking into account all the physical aspects of the dynamics of a ferromagnetic system has also been developed for the study of both quasi-equilibrium transitions and large magnetization jumps (highly non-equilibrium processes). Finally, the described method has been checked comparing simulations to analytically solved problems (sphere, infinite cylinder) and to experimental observations (on cobalt submicronic magnets), obtaining in both cases a very good agreement.

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