J. Phys. IV France 07 (1997) C1-601-C1-602
Magnetite Fe3-δO4 : a Stoichiometry and Structure Analysis of MBE Grown Thin Films Using NO2 as the Oxidising SourceF.C. Voogt1, T. Hibma1, P.J.M. Smulders1, L. Niesen1, T. Fujii2, P.A.A. van der Heijden3, R.J.M. van de Veerdonk3 and P.J. van der Zaag3
1 Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
2 Laboratory of Solid State Chemistry, Department of Applied Chemistry, Faculty of Engineering, Okayama University, Tshushima-naka 3-1-1, Okayama 700, Japan
3 Philips Research Laboratories Eindhoven, Prof. Holstlaan 4, 5656 AA, Eindhoven, The Netherlands
Epitaxial single crystalline films of iron oxides have been grown on MgO(100) substrates by means of MBE. Natural Fe or 57Fe was evaporated from alumina crucibles, and oxidised simultaneously with a dosed flux of NO2. The resulting oxide layers have been characterised in situ with RHEED, LEED, XPS, and AES. RHEED intensity oscillations, observed during deposition of the oxides, indicate a layer-by-layer growth for all substrate temperatures between 373 and 673 K. A stoichiometry analysis with CEMS, performed ex situ, shows that it is straightforward to prepare both the stable magnetite Fe3O4 and the metastable maghemite Fe3-δO4 phases. Moreover, also al1 solid solutions in between these two extreme phases, i.e. Fe3-δO4 with 0<δ<1/3, could be formed. Ion beam channelling has been used to examine the epitaxy of the films. It was found that the films grow coherent on MgO(100).
© EDP Sciences 1997