Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 48: Oxide und Isolatoren II
O 48.8: Vortrag
Dienstag, 8. März 2005, 17:30–17:45, TU EB107
Surface x-ray analysis of Co grown on NiO(100) — •Christian Tusche1, Holger Meyerheim1, Jürgen Kirschner1, Ulrich Hillebrecht2, and Carlos Quiros3 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle — 2Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich — 3ESRF, 6 rue Jules Horowitz, F-38043 Grenoble
Ultra-thin ferromagnetic films grown on antiferromagnetic oxides are of interest for fundamental studies of exchange biased systems. Still the role of the microscopic structure of the metal/oxide interface is subject to discussion. Of particular interest is the well known antiferromagnet NiO with thin overlayers of the ferromagnetic elements Fe, Co, Ni.
We have carried out a surface x-ray structure analysis of the Co/NiO(100) interface. About one monolayer of Co was deposited at room temperature on the nonpolar NiO(100) surface. The formation of two layer high CoO islands covering about 25% of the surface area is observed. The interfacial region consists of about one monolayer of a substoichiometric mixed oxide [NiCo]Ox with x≈ 0.5. Comparing with bulk NiO the interlayer spacing is expanded by 9%.
The oxygen deficiency in the interface region gives strong evidence for the presence of metal-like Ni and Co in the interface. By formation of uncompensated interfacial spins, this is generally considered to play a major role in exchange bias effects.