Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 52: Magnetic Materials IV

MA 52.8: Vortrag

Freitag, 4. April 2014, 11:15–11:30, HSZ 403

The giant magnetoimpedance of iron single crystals — Matthäus Langosch, Thomas Karwoth, •Haibin Gao, and Uwe Hartmann — Institute of Experimental Physics, Saarland University, P. O. Box 151150, D66041, Saarbrücken, Germany

Extended magnetoimpedance measurements on iron single crystals with <100> growth direction were performed at room temperature as a function of the applied longitudinal magnetic field and of the applied current frequency. In the chosen frequency regime, it is found that there is a maximum magnetoimpedance ratio of more than 150% under the chosen experimental conditions. To investigate the origin of the effect, magneto-optic Kerr effect (MOKE) microscopy experiments were performed to study the contribution of the magnetic domain structures and domain wall movement. The investigations show that, apart from the well-known Landau structures and the sheath-core one, mixed magnetic domain structures are existing as well. A detailed analysis of the MOKE images indicates that the structures have a helical shape. In addition, calculations based on the standard skin effect formalism permit the determination of the magnitude and the phase of the effective circumferential permeability. The resulting values of the effective circumferential permeability make it possible to distinguish between different regimes dependent on the external longitudinal magnetic field and the magnitude of the applied current.