Abstract
We have investigated the magnetic behavior of semi-metallic CrO2 powder samples as a function of Ar sputtering at low kinetic energy. By the use of X-ray absorption spectroscopy at the O K edge and X-ray magnetic circular dichroism at the Cr L2,3 edges as a function of sputtering time, a strong decrease of the absolute magnetic moment has been observed corresponding to a surface reduction to a Cr2O3- like compound, deduced by chemical shifts in the X-ray absorption spectra. An unexpected change of sign of the Cr L2,3 dichroism signal was found and interpreted by the formation of an antiparallel coupled ferromagnetic top layer. By comparison with epitaxial grown CrO2 films a quantitative estimation of the initial Cr2O3 toplayer thickness is possible.
Abstract
Es wurde das magnetische Verhalten von CrO2-Pulverproben unter Einfluss des Oberflächensputterns mit Ar-Ionen bei niedriger kinetischer Energie untersucht. Durch Röntgen-Absorptionsspektroskopie an der O-K-Kante und mittels magnetischem Röntgen-Zirkular-Dichroismus (XMCD) an den Cr-L2,3-Kanten als Funktion der Sputterzeit konnte ein starke Abnahme des absoluten magnetischen Momentes beobachtet werden, was auf eine Reduktion der Oberfläche zu einer Cr2O3 ähnlichen Verbindung zurückgeführt werden konnte. Diese Reduktion wurde in einer chemischen Verschiebung des Röntgen-Absorptionsspektrums nachgewiesen. Das Cr-L2,3-Spektrum zeigte nach dem Sputtern einen unerwarteten Vorzeichenwechsel, der durch eine zum inneren CrO2 antiparallel orientierte und ferromagnetisch geordnete Oberflächenschicht interpretiert werden konnte. Durch den Vergleich mit epitaktisch gewachsenen Filmen konnte die ursprüngliche Cr2O3-Dicke der Deckschicht der ungesputterteten Probe abgeschätzt werden.
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We would like to thank H. Gundlach for kind user support at BESSY, F. Weigand and J. Geissler for helpful discussions, and A. Fuss for support at the beam time. This work was performed at and supported by BESSY GmbH. Additional financial support by DFG (Schu 964/2-3).
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© 2002 Carl Hanser Verlag, München
Articles in the same Issue
- Frontmatter
- Editorial
- Editorial
- Max-Planck-Institut für Metallforschung
- Articles/Aufsätze
- Towards a micromechanical understanding of biological surface devices
- Solid state phase transformation kinetics: a modular transformation model
- Electronic structure investigations of Ni and Cr films on (100)SrTiO3 substrates using electron energy-loss spectroscopy
- Surface magnetization reversal of sputtered CrO2
- Magnetic imaging with full-field soft X-ray microscopy
- Dislocation dynamics in sub-micron confinement: recent progress in Cu thin film plasticity
- Fatigue behavior of polycrystalline thin copper films
- Grain growth in magnetron-sputtered nickel films
- Thin Pd films on SrTiO3 (001) substrates: ab initio local-density-functional theory
- Coupled grain boundary and surface diffusion in a polycrystalline thin film constrained by substrate
- Gallium segregation at grain boundaries in aluminium
- Current work at the Stuttgart UHV diffusion bonding facility
- Bonding between Cu and α-Al2O3
- Compressive deformation of niobium sandwich-bonded to alumina
- SiO2-coated carbon nanotubes: theory and experiment
- Simulation of solidification structures of binary alloys
- Gaseous nitriding of iron-chromium alloys
- Deposition of ceramic materials from aqueous solution induced by organic templates
- Notifications/Mitteilungen
- Personen
- Books
- Information
- DGM Further Training
Articles in the same Issue
- Frontmatter
- Editorial
- Editorial
- Max-Planck-Institut für Metallforschung
- Articles/Aufsätze
- Towards a micromechanical understanding of biological surface devices
- Solid state phase transformation kinetics: a modular transformation model
- Electronic structure investigations of Ni and Cr films on (100)SrTiO3 substrates using electron energy-loss spectroscopy
- Surface magnetization reversal of sputtered CrO2
- Magnetic imaging with full-field soft X-ray microscopy
- Dislocation dynamics in sub-micron confinement: recent progress in Cu thin film plasticity
- Fatigue behavior of polycrystalline thin copper films
- Grain growth in magnetron-sputtered nickel films
- Thin Pd films on SrTiO3 (001) substrates: ab initio local-density-functional theory
- Coupled grain boundary and surface diffusion in a polycrystalline thin film constrained by substrate
- Gallium segregation at grain boundaries in aluminium
- Current work at the Stuttgart UHV diffusion bonding facility
- Bonding between Cu and α-Al2O3
- Compressive deformation of niobium sandwich-bonded to alumina
- SiO2-coated carbon nanotubes: theory and experiment
- Simulation of solidification structures of binary alloys
- Gaseous nitriding of iron-chromium alloys
- Deposition of ceramic materials from aqueous solution induced by organic templates
- Notifications/Mitteilungen
- Personen
- Books
- Information
- DGM Further Training