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MA: Magnetismus

MA 10: Micromagnetism / Computational Magnetism

MA 10.2: Talk

Monday, March 27, 2006, 17:15–17:30, HSZ 401

Ferromagnetic Hollow Cylindrical Nanoparticles — •D. Goll, G. Schütz, and H. Kronmüller — Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, 70569 Stuttgart, Germany

Magnetic ground states of hollow cylindrical nanoparticles with a nonmagnetic core have been analytically calculated on the basis of the theory of micromagnetism. As a function of the three material parameters, spontaneous polarization, magnetocrystalline anisotropy constant and the exchange constant, the phase diagrams of three types of magnetic configurations have been determined. For uniaxial perpendicular anisotropy a single-domain homogeneous state, a curling configuration and a homogeneous multidomain state may exist as a function of the above material constants. The critical radii where the transitions between these configurations take place are determined as a function of the material parameters. The special cases of soft and hard magnetic materials are discussed in relation to the exchange lengths. The analytical results are compared with numerical micromagnetic simulations on the basis of the finite element method.