Europhys. Lett.
Volume 68, Number 2, October 2004
Page(s) 233 - 239
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 October 2004
Europhys. Lett., 68 (2), pp. 233-239 (2004)
DOI: 10.1209/epl/i2003-10312-y

Enhanced exchange bias due to an ultra-thin, non-magnetic insulator spacer layer

A. Paul, D. E. Bürgler, M. Luysberg and P. Grünberg

Institut für Festkörperforschung - Forschungszentrum Jülich GmbH D-52425 Jülich, Germany

received 11 December 2003; accepted in final form 27 August 2004

The exchange bias effect of $\chem{Co/CoO}$ bilayers is found to significantly increase when an ultra-thin, non-magnetic insulating $\chem{AlO}$ x spacer is added at the ferromagnet/antiferromagnet interface. The dependence on the spacer thickness is non-monotonic with a maximum two-fold enhancement of the exchange bias field $H_{\ab{EB}}$ at a spacer thickness of 1.0 $\un{nm}$. These observations are explained in terms of a discontinuous layer structure of the spacer and its thickness evolution. There is no indication of a magnetic interaction across the $\chem{AlO}$ x spacer layer.

68.65.Ac - Multilayers.
75.30.Gw - Magnetic anisotropy.
75.70.Cn - Magnetic properties of interfaces (multilayers, superlattices, heterostructures).

© EDP Sciences 2004