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R. Grössinger:
"Magnetoelectric Materials";
Vortrag: Seminar Institut für Allgemeine Physik (IAP), TU Wien; 25.04.2006.

Magnetoelectric materials become magnetized when placed in an electric field, and electrically polarized when placed in a magnetic field. This effect can occur in single phase materials (as e.g. Cr2O3) which need special symmetry conditions for the lattice. The ME effect obtained in composites is more than a hundred times stronger that of single-phase ME material.
An overview over this new family of materials will be given. Also the appropriate measuring methods for the material characterisation (magnetostriction as well as piezoelectric constant) will be described. The magnetoelectric constant is measured in a static field produced by an electromagnet superimposing an ac-field. In this case a voltage appears on the surface of the sample that can be detected using a lock-in amplifier. Additionally a pulsed field method was developed, which allows the direct observation of the magnetoelectric constant. Representative results on composites of CoFe2O4-BaTiO3 will be shown and discussed.