Berlin 2012 – scientific programme

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MA: Fachverband Magnetismus

MA 13: Magnetic Materials

MA 13.3: Talk

Monday, March 26, 2012, 15:30–15:45, H 0112

Domain-structure-induced giant magneto-impedance of iron whiskers — •Matthäus Langosch, Haibin Gao, and Uwe Hartmann — Institute of Experimental Physics, Saarland University, P. O. Box 151150, D-66041, Saarbrücken, Germany

Specific contributions to the giant magneto-impedance (GMI) effect, especially those being due to domain wall motion, should further be investigated in order to better understand this interesting effect. For this purpose, soft magnetic materials were studied at low frequencies leading mainly to contributions of domain wall motion. These are not relevant to the effect at high frequencies as normally applied. Iron single crystals (iron whiskers) were grown as specific samples to investigate the GMI effect with AC currents up to 100 kHz. The magnitude of the currents was large enough to modify the whiskers' domain structure by the Oersted fields. We give an overview not only of the impedance components obtained but also of the magnitude and the phase of the effective circumferential permeability. The latter is obtained through calculations based on the standard skin effect formalism and on the experimental data. We further discuss relevant domain configurations, domain wall motions and their relations to the applied longitudinal magnetic field, the AC current magnitude and its frequency.