Berlin 2005 – scientific programme

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MA: Magnetismus

MA 29: Magnetische Materialien

MA 29.10: Talk

Tuesday, March 8, 2005, 17:30–17:45, TU A060

TEXTURE IN FINE GRAINED NdFeB PERMANENT MAGNETS — •Kirill Khlopkov, Oliver Gutfleisch, Dietrich Hinz, Karl-Hartmut Müller, and Ludwig Schultz — IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany

Melt-spun die-upset NdFeB magnets represent a nearly ideal system for the systematic study of texture in relation to the magnetic properties and the magnetic microstructure since various degrees of texture can be easily adjusted by hot deformation (die-upsetting to various strains or different height reductions). The degree of texture has been defined as the ratio between the respective remanent magnetisations measured in the two directions, perpendicular and parallel to the deformation direction. For the magnet with the highest degree of texture a local texture analysis using electron back scatter diffraction (EBSD) has been performed. Magnetic force microscopy (MFM) has been used to examine the dependence of magnetic microstructure on texture in the thermally and dc-demagnetised states. A very fine contrast on a scale of 300 nm can be resolved with MFM even in isotropic magnets. Magnets with higher degree of texture show broad and well-pronounced interaction domains. The phase shift of the MFM cantilever increases linearly with the width of interaction domains. Two types of magnetic microstructure (regions with fine contrast and interaction domains extension over more than 2 microns) have been observed in the dc-demagnetised state. The dependence of these cooperative phenomena on texture is discussed. This work was supported by SFB463.