Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 4: Magnetic Coupling Phenomena; Exchange Bias

MA 4.2: Vortrag

Montag, 25. Februar 2008, 10:30–10:45, H 1028

Chemical Order-Induced Magnetic Exchange Bias — •Dieter Lott¹, Frank Klose^2,3, Hailemarian Ambaye³, Gary J. Mankey⁴, Prakash Mani⁴, Max Wolff⁵, Andreas Schreyer¹, Hans M. Christen³, and B.C. Sales³ — ¹GKSS Research Center, Max-Planck Str. 1, 21502 Geesthacht, Germany — ²ANSTO, Bragg Institute, Menai, NSW, 2234, Australia — ³Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA — ⁴MINT Center, University of Alabama, Tuscaloosa, AL, 35487, USA — ⁵Department of Physics, Ruhr-University Bochum, 44780 Bochum, Germany

We report on chemical order-induced magnetic exchange bias in FePt3, a material which - due to partial chemical disorder - has both ferromagnetic (FM) and antiferromagnetic (AFM) domains. Epitaxial thin films of this material were investigated by polarized neutron reflectivity and SQUID magnetometry in a superlattice system consisting of FePt3 and ferromagnetic CoPt3 layers. The onset of AFM order in the chemically ordered part of the FePt3 layers induces a strong exchange bias of the hysteresis loop. We demonstrate that the observed exchange bias originates intrinsically from within the FePt3 layer, i.e. we observe exchange bias between two different magnetic phases of a single crystal material having virtually the same chemical composition.