Regensburg 2004 – scientific programme
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MA: Magnetismus
MA 10: Exchange Bias
MA 10.2: Talk
Tuesday, March 9, 2004, 10:30–10:45, H10
Soft X-ray Resonant Magnetic Scattering studies on CoO/Fe exchange bias bilayers — •Florin Radu, Gregor Nowak, Johannes Grabis, Alexei Nefedov, and Hartmut Zabel — Experimentalphysik/Festkoerperphysik, Ruhr-Universitaet Bochum, 44780 Bochum, Germany
We have used the ALICE diffractometer and soft X-ray Resonant Magnetic Scattering (XRMS) techniques to search for the presence of an effective ferromagnetic moment in an antiferromagnetic (AF) layer which is in close contact with a ferromagnetic (F) layer. Using rf-sputtering we have prepared two samples in a single run: one is a CoO(25 Å)/Fe(150 Å) exchange bias system and the other is a single CoO(25 Å) AF layer deposited on a sapphire substrate. The samples were cooled in a field of +2000 Oe from above the TN=291 K of the CoO AF layer to T=30 K. Taking advantage of the element specificity of the XRMS technique, we have measured hysteresis loops of both Fe and CoO layers. The result is that a single layer of CoO deposited on a substrate shows no ferromagnetic signal while for the CoO layer deposited on the Fe ferromagnetic layer we observe hysteresis loops. From these measurements we conclude that the proximity of the F layer induces a magnetic moment in the AF layer. The F moment in the AF layer has two components: one is frozen and does not follow the applied magnetic field and the other one follows in phase the ferromagnetic magnetization of the F layer. This work was supported by SFB 491 and BMBF03ZAE7BO.