Berlin 2008 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 4: Magnetic Coupling Phenomena; Exchange Bias
MA 4.4: Vortrag
Montag, 25. Februar 2008, 11:00–11:15, H 1028
Combined magnetic X-ray scattering and polarized neutron diffraction study of the origin of extinct exchange bias in the epitaxial Py(111)/CoO(111) bilayer — •F. Radu1, S. K. Mishra1, I. Zizak1, A. I. Erko1, H. A. Dürr1, W. Eberhardt1, D. Schmitz2, E. Schierle2, S. Buschhorn3, G. Nowak3, M. Wolff3,4, K. Zhernenkov3,4, and H. Zabel3 — 1BESSY GmbH, Albert-Einstein Strasse 15, D-12489, Berlin, Germany — 2Hahn Meitner Institut, Glienicker Str. 100, D-14109 Berlin, Germany — 3Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität, Bochum, D-44780 Bochum, Germany — 4Institut Laue-Langevin, F-38042 Grenoble Cedex 9, France
We have employed Soft X-ray Resonant Magnetic Scattering (XRMS), Polarised Neutron Diffraction (PND) and Reflectivity (PNR) to study the magnetic interface and the bulk AF domain state of the archetypal epitaxial Py(111)/CoO(111) exchange bias (EB) bilayer. The exchange bias field extracted from the magnetization curve is several orders of magnitude lower than expected. The element specific hysteresis loops exhibit a vertical shift for the CoO interface which appears at the onset of the exchange bias field, at the blocking temperature. PNR resolves the magnetization reversal which proceeds by nucleation and domain wall movement at both branches of the hysteresis loop. PND on the CoO (1/2 1/2 1/2) magnetic Bragg peak reveals an isotropic in-plane orientation for the 3.5 nm thick AF domains. This particular AF domain state provides a virtually compensated interface for the F layer which explains the low EB field.