Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 25: Oxide and Insulator Surfaces: Structure and Growth
O 25.1: Poster
Montag, 7. März 2016, 18:15–20:30, Poster E
Oxidation of epitaxial iron films on Ag(001) — •Jari Rodewald, Daniel Bruns, and Joachim Wollschläger — Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany
Ferrimagnetic magnetite Fe3O4 with inverse spinel structure is a promising candidate for magnetic devices like giant magneto resistance (GMR) and tunneling magneto resistance (TMR). In order to develop these devices and to select certain iron oxide phases it is important to understand the structure and growth properties of such oxide films.
Hence, this work investigates the oxidation process of crystalline iron films with respect to different annealing temperatures and oxygen pressures. Therefore, pure bcc-iron is deposited on Ag(001) substrates by molecular beam epitaxy (MBE) and the oxidation process is divided into three consecutive steps of pre-annealing, UHV-annealing and post-annealing.
Surface structure and morphology are analyzed by spot profile analysis low energy electron diffraction (SPA-LEED), while the chemical composition of the surface is investigated by Auger electron spectroscopy (AES). Additionally, grazing incidence x-ray diffraction (GIXRD) measurements are performed in order to obtain
information on the bulk structure of the deposited films.
The largest amount of magnetite is generated by post-annealing at 400∘C and an oxygen pressure of 1·10−5 mbar, while higher temperatures reduce the amount of oxygen and induce a structural change at the surface.