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 20.51: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU C
Coercivity and exchange bias of ferromagnetic/antiferromagnetic multilayers — •Ulrich Nowak, Gregor Scholten, and Klaus D. Usadel — Fachbereich Physik, Universität Duisburg-Essen, 47058 Duisburg, Germany
For a model system consisting of a ferromagnetic layer exchange coupled to an antiferromagnetic layer with a compensated interface detailed mean field type calculations are performed. For the coercive field a rather broad enhancement around the Néel temperature TN of the antiferromagnetic layer is found irrespectively of whether the antiferromagnetic layer is structurally disordered or not, while exchange bias is only found for systems with defects. The results for the exchange bias field are in qualitative agreement with those obtained previously with Monte Carlo simulations [1,2].
With some simplifying assumptions, we can obtain from this approach analytic results for the coercive field and the exchange bias field. We show that the observed enhancement of the coercivity around TN and the occurrence of exchange bias are of different origin.
Work supported by the Deutsche Forschungsgemeinschaft through SFB 491.
[1] P. Miltenyi, M. Gierlings, J. Keller, B. Beschoten, G. Güntherodt, U. Nowak, and K. D. Usadel, Phys. Rev. Lett. 84, 4224 (2000).
[2] U. Nowak, K. D. Usadel, P. Miltényi, J. Keller, B. Beschoten, and G. Güntherodt, Phys. Rev. B 66, 14430 (2002).