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MA: Magnetismus

MA 11: Magnetische Materialien

MA 11.8: Vortrag

Dienstag, 9. März 2004, 12:00–12:15, H22

Interaction domains in NdFeB magnets in dependence on the degree of texture — •Kirill Khlopkov, Oliver Gutfleisch, Dietrich Hinz, Axel Handstein, Karl-Hartmut Müller, and Ludwig Schultz — IFW Dresden, Postfach 270016, 01171 Dresden

The magnetic domain structure of die-upset NdFeB magnets with different degrees of texture has been investigated using the magneto-optical Kerr effect and magnetic force microscopy (MFM). For the non-textured i.e. isotropic hot pressed starting material interaction domains could not yet be observed by optical Kerr-microscopy. Interaction domains could be observed by Kerr-microscopy in die-upset samples with a deformation degree of more than 52% (medium degree of texture). In contrast MFM reveals the presence of interaction domains already for considerably lower degrees of texture. Magnetostatic interaction is assumed to cause the interaction domains since the grains are separated by thin amorphous Nd-rich grain boundaries of about 1 nm thickness which are expected to suppress exchange coupling between the grains. The interaction domains are cooperative phenomena on a length scale much larger than the grain size of typically 100 nm × 400 nm for highly textured sample with a deformation degree of about 76%.

This work was supported by SFB463.