Als eine neue Fragestellung wird der Einbau von Erbium (0,4 %) in Scan diumoxid (Sc2O3 ) untersucht. Dabei wird festgestellt, daß Erbium nicht wie aufgrund seiner chemischen Eigenschaften angenommen, substitutionell in den Kristall eingebaut wird. Es besetzt vielmehr einen Zwischengitterplatz, der an eine Sauerstoff Leerstelle gekoppelt ist.
Conceptual and experimental development of a holographic me thod in Xray structure determination For several years Xray diffraction is the most common approach for structure analysis of crystalline samples. Still structure determination always requires a model as a starting point, due to the so called crystallographic phase problem. This is different in Holography, where phase information is obtained from the interference between the wave scattered from the object and a well known reference wave.
A new method is presented here, which interpretes Bragg scattering pat terns of crystalline samples in a holographic way. It is provided that a part of the electron density in the unit cell is known. The wave scattered from this part interferes with the wave, scattered from the unknown part of the electron density. They are called reference and object wave in analogy to holography. The measured intensity then contains information about the phase of the object wave, which is achievable by the knowledge of the reference wave. In contrast to e.g. holography with visible light the underlying electron density can only be reconstructed numerically. Similarities between this approach and methods of crystallography, imagerecovery and atomic resolution Xray holography are discussed. This approach is then extended to study the non periodic structure of point defects in inorganic crystals. The capability of this approach is demonstrated in several examples using both, simulated and measured data. The accuracy and the reliability of this method are derived in this way.
The incorporation of Erbium (0.4 %) in Scandiumoxide (Sc2O3 ) is stu died as a new subject. It is found that Erbium, which was expected to be built in substitutionally due to its chemical properties, can be located in an interstitial position. This position is coupled with an oxygen vacancy.