Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)

MA 15.27: Poster

Tuesday, March 27, 2007, 15:00–19:00, Poster A

Analysis of the structure and stoichiometry in iron/native iron oxide multilayers — •Thomas Diederich, Sebastien Couet, and Ralf Röhlsberger — Hamburger Synchrotron Strahlungslabor (HASYLAB) at Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607 Hamburg

Recently we have found that multilayers consisting of iron and native iron oxide layers exhibit a magnetic superstructure [1]. It is clear that the mechanism leading to the observed coupling strongly depends on the multilayer structure and the properties of the native iron oxide. In order to characterize the multilayers in more detail we have used different X-ray techniques at the DORIS storage ring (DESY, Hamburg) such as X-ray absorption spectroscopy (XAS) and X-ray reflectometry (XRR). By using reference samples for XAS measurements at the Fe K-edge we have been able to extract the absorption profile resulting from the oxide in the multilayer. From this we conclude that the native oxide is a mixture of FeO and Fe₃O₄ with a ratio of about 1:1. The XRR experiments have been used to characterize the structure of the multilayer. Superstructure Bragg peaks in the reflectivity data arise due to the chemical periodicity. From a simulation of the data we found average thicknesses of 1.7 nm and 1.6 nm for the Fe and the Fe-oxide layers, respectively. The interface roughness is about 0.4 nm for the bottom layers and increases to roughly 0.7 nm for the upper layers.

[1] Th. Diederich, S. Couet, and R. Röhlsberger, submitted