Regensburg 2004 – wissenschaftliches Programm

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MA: Magnetismus

MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)

MA 13.45: Poster

Dienstag, 9. März 2004, 15:00–19:00, Bereich A

Electric control of exchange bias — •Andreas Hochstrat, Christian Binek, Xi Chen, Pavel Borisov, and Wolfgang Kleemann — Universität Duisburg-Essen, Campus Duisburg, Fakultät für Naturwissenschaften, Institut für Physik, Laboratorium für Angewandte Physik, 47048 Duisburg

Electric field controlled exchange bias is studied on Molecular Beam Epitaxy grown magnetic heterostructures based on antiferromagnetic Cr₂O₃, the prototypical system for investigations of the magneto-electric effect. An electric field E applied to the sample gives rise to an additional magnetic moment in the antiferromagnetic component. The magneto-electric coefficient as a function of temperature is investigated using Superconducting Quantum Interference Device (SQUID) magnetometry. In accordance with the phenomenological approach of Meiklejohn and Bean the additional magnetic moment is the origin for electric access to the exchange bias. The effect of antiferromagnetic domain states on the controllability of the exchange bias is explored by SQUID-magnetometry. Magneto-electrically annealed antiferromagnetic single domain states reveal exchange bias fields, which depend on the freezing conditions, but remain virtually independent of E below the blocking temperature. However, preparation of a magneto-electric multi-domain state enables substantial electric control of the exchange bias in the frozen state which is probably due to flopped domain wall spins.