DFG Research Group: Project 1

Crystal Preparation and Characterization

Prof. Dr. Siegfried Horn, Dr. Matthias Klemm

This project is part of an effort to establish the relationship between structural and electronic properties of transition metal oxides. It is concerned with the preparation and structural characterization of transition metal oxides, primarily vanadium oxides. Samples are prepared as polycrystals, single crystals and thin films. Techniques involved are solid state reactions for polycrystals, the gradient freeze method or chemical transport reactions for single crystals and electron beam evaporation for thin film growth on various substrates. The structural characterization is carried out by x-ray diffraction and x-ray absorption (near edge structure and extended x-ray absorption fine structur) measurements in the soft- and hard x-ray regime, as well as low energy electron diffraction and scanning electron microscopy. Typical systems of interest are: V2O3 and VO2 (metal-insulator transition), LiV2O4 (heavy fermion behavior), and NaV2O5 (one dimensional spin-Peierls).