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MA: Fachverband Magnetismus
MA 11: Magnetic Materials
MA 11.8: Talk
Monday, March 23, 2009, 17:00–17:15, HSZ 103
Interaction Domains in High Performance NdFeB Thick Films — •Tom Woodcock1, Kirill Khlopkov1, Arno Walther2,3, Nora Dempsey2, Dominique Givord2, Ludwig Schultz1, and Oliver Gutfleisch1 — 1IFW Dresden, IMW, P.O. Box 270116, 01171 Dresden, Germany — 2Insitut Néel, CNRS-UJF, 25 ave. de Martyrs, 38042, Grenoble, France — 3CEA Léti - MINATEC, 17 rue des Martyrs, 38054 Grenoble, France
Thick sputtered films (5-300 micron) of NdFeB have excellent hard magnetic properties which make them attractive for applications in micro-electro-mechanical systems (MEMS). A two step process consisting of triode sputtering and high temperature annealing produced films with energy densities approaching those of sintered NdFeB magnets.
Magnetic force microscopy (MFM) using hard magnetic tips showed that the films deposited without substrate heating and at 300°C exhibited magnetic domains typical of low anisotropy materials. These films were amorphous in the as-deposited state. The film deposited at 500°C was crystalline and displaid hard magnetic properties. This was reflected in the magnetic microstructure which showed interaction domains typical of highly textured and high magnetic anisotropy materials with a grain size below or equal to the critical single-domain particle limit. With increasing substrate temperature, the domain patterns of the annealed films became coarser, indicating higher degrees of texture.