Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65
MA 20.154: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU C
Modelling the Procopiu Effect — •J. Velleuer, A. Hackl, and E. Kisker — Institut für Angewandte Physik, Heinrich-Heine Universität Düsseldorf, 40225 Düsseldorf
The Procopiu effect [1], used for very sensitive magnetic field sensing, manifests itself in the occurrence of an AC voltage on a solenoid wrapped around a softmagnetic wire, when an AC current is flowing through the wire and an external magnetic field (Hz) is applied. The magnitude of the voltage increases quasilinearly from very small values at Hz=0 until two maxima symmetrical to Hz=0 are observed at about the earth magnetic field strength. At the same time, the wire exhibits the giant magnetoimpedance (GMI) effect [2] which, at frequencies above about 500 kHz, also shows two maxima at some small magnetic field strength, also symmetrical to zero field. We are able to model the Procopiu effect quantitatively using only the magnetic material properties. Whereas the maxima in the GMI effect are considered to arise from the coercive field of the softmagnetic wire, the maxima in the Procopiu voltage are shown to originate already from a non-hysteretic magnetization curve. This suggests that the Procopiu effect and the GMI effect arise from different shells of the wire, i.e. the former from the magnetic core and the latter from the outer shell as a consequence of the skin effect. [1] see, e.g.: J. J. Freijo, J. Appl. Phys. 85, 5450 (1999) [2] see, e.g.: C. Bethke et al., Technisches Messen 70, 12 (2003)