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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 20.50: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU C
Azimuthal dependence of exchange bias and coercive field of Fe(110)/CoO(111) exchange bias bilayer — •Gregor Nowak, Florin Radu, Kurt Westerholt, and Hartmut Zabel — Experimentalphysik/Festkörperphysik, Ruhr-Univeristät Bochum, 44780 Bochum
We have prepared epitaxial Fe(110)/CoO(111) bilayers and
characterized their structure by x-ray diffraction. Structurally,
the bilayer shows a single domain growth for the CoO layer with
six-fold in-plane symmetry. The Fe layer, however, shows a
Nishiyama-Wassermann growth of three equivalent domains. The
exchange bias (EB) properties were investigated by SQUID
magnetometry. First, we measured the EB field as a function of
the field cooling direction. The EB field exhibits a twofold
symmetry which defines the uniaxial anisotropy orientation of the
AF layer. Then we cooled down the system for different
orientations of the applied field with respect to the uniaxial
axis of the AF layer. For each field-cooling orientation we
recorded hysteresis loops as a function of the azimuth angle of
the sample with respect to the applied field. The maximum EB
field is not found along the field cooling direction instead we
observed this maximum to be parallel to the easy axis of the AF
layer. This is in very good agreement with the theoretical
predictions of Nowak and Usadel1. Also, the unidirectional
behaviour of the EB field shows modulations created by the
uniaxial nature of the AF layer anisotropy.
1B. Beckmann, U. Nowak, and K. D. Usadel , Phys. Rev. Lett. 91,
187201 (2003).
This work was supported by SFB 491.