Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 19: Micro Magnetism / Computational Magnetism

MA 19.3: Talk

Wednesday, March 25, 2009, 10:45–11:00, HSZ 403

Nanostructured FePt/Fe composite particles for ultrahigh density magnetic recording — •Dagmar Goll, Gisela Schütz, and Helmut Kronmüller — MPI für Metallforschung, Stuttgart, Germany

Composite particles based on bilayers consisting of a magnetically hard and a magnetically soft layer are promising candidates for realizing the main conditions for ultrahigh density magnetic recording: Thermal stability of > 10 a, coercive fields of 1 - 1.5 T and switching times in the subns region. FePt/Fe composite particles are predestinated to fulfill these conditions if the microstructure is designed suitably. In particular the coercive field may be tailored either by varying the thickness of the soft layer or by manipulating the width of the phase boundary between the soft and the hard magnetic layer. Both methods have been investigated experimentally and by analytical and computational micromagnetism. It is shown that the thickness dependence of the coercive field follows a 1/d_soft^3/2 law (d_soft: thickness of the soft layer) for particles with lateral dimensions larger than the thickness of the particle and a 1/d_soft law for particles where lateral dimensions and the particle thickness are comparable with each other.