Berlin 2005 – scientific programme

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MA: Magnetismus

MA 27: Spindynamik II

MA 27.5: Talk

Tuesday, March 8, 2005, 16:15–16:30, TU H1012

Dynamic losses and domain refinement in nanocrystalline tape wound cores — •Sybille Flohrer¹, Rudolf Schäfer¹, Jeffrey McCord¹, Stefan Roth¹, Giselher Herzer² und Ludwig Schultz¹ — ¹Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstraße 20, D-01069 Dresden, Germany — ²VACUUMSCHMELZE GmbH & Co. KG, Grüner Weg 37, D-63450 Hanau, Germany

The analysis of dynamic magnetization processes is the basis for the understanding of energy loss mechanisms in magnetic materials. Stroboscopic Kerr-microscopy observations on a variety of nanocrystalline Fe₇₃Cu₁Nb₃Si₁₆B₇ tape wound cores with different strengths of the induced longitudinal anisotropy are presented. In the frequency range from the quasi-static case up to 10 kHz domain refinement is distinctive. The correlation between domain refinement, the strength of the induced anisotropy, and the cycle losses is studied. The strongest wall multiplication is observed in the cores with the weakest induced anisotropy, where the wide domains even decay into a patchy pattern at elevated frequencies. The arising of the patchy domains is discussed in terms of the induction rate and the influence of residual anisotropies.