Dresden 2006 – scientific programme

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MA: Magnetismus

MA 36: Magnetic Coupling Phenomena / Exchange-Bias

MA 36.4: Talk

Friday, March 31, 2006, 11:30–11:45, HSZ 401

Fundamental Aspects of the Exchange Bias Effect — •Florin Radu¹ and Hartmut Zabel² — ¹BESSY GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany — ²Department of Physics, Ruhr-University Bochum, D-44780 Bochum, Germany

We have reconsidered the Meiklejohn and Bean for the exchange bias effect and we have extended it to account for the coercivity enhancement observed in almost all F/AF systems. The essential modification is that the anisotropy of the AF layer is not sharp at the interface, but it decreases from a maximum inside of the AF layer to zero inside of the F layer. Such an interface layer should have properties different from either the AF and F layer. We have assumed it to be a spin glass-like layer. The reduced AF anisotropy at the F/AF interface leads to a dramatic change of the EB field as function of the magnetic state of the F/AF interface described by a conversion factor. The model based on this concept is able to reproduce the peak of the EB field at the critical thickness and/or critical anisotropy of the AF layer. Furthermore, the training effect can be qualitatively reproduced assuming a progressively increasing magnetic disorder at the interface.