Regensburg 2004 – scientific programme
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MA: Magnetismus
MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)
MA 13.42: Poster
Tuesday, March 9, 2004, 15:00–19:00, Bereich A
Growth and structural properties of epitaxial CoO(111) thin films on sapphire substrates — •Gregor Nowak, Florin Radu, Kurt Westerholt, and Hartmut Zabel — Experimentalphysik / Festkörperphysik, Ruhr - Universität Bochum, Deutschland
Although CoO is widely used as antiferromagnetic layer in exchange biased heterostructures, a systematic study of the growth-property relationship has not been reported yet. We used rf-sputtering techniques for the deposition of CoO films on Al2O3(00.1) substrates. By varying the partial oxygen pressure we could change the stoichiometry, which results in a variation of the ferromagnetic signal. We have optimized the partial oxygen pressure as to have minimum ferromagnetic signal of the antiferromagnetic CoO layer. In addition, the substrate temperature was varied between 100 ∘C to 600 ∘C to optimized the structural parameters. We observe the best quality of CoO at about 400 ∘C. The samples were studied by x-ray reflectivity and x-ray diffraction. We find an improved crystallinity of the CoO(111) layer on Al2O3(00.1), as recognized by (00l) Bragg peaks accompanied by Laue oscillations. Small angle reflectivity measurements reveal very small roughness values of 0.5-0.6 nm for a 20 nm thick film, has been confirmed by AFM measurements. Determination of the exchange field as a function of stoichiometry and growth temperature is in progress. This work was supported by SFB 491