Characterization of an Yb:LuVO4 single crystal using X-ray topography, high-resolution X-ray diffraction, and X-ray photoelectron spectroscopy

摘要

Knowledge on the defect and electronic structure allows for improved modeling of material properties. A short literature review has shown that the information on defect structure of rare earth orthovanadate single crystals is limited. In this paper, defect and electronic structure of a needle-shaped Yb:LuVO4 single crystal grown by the slow cooling method have been studied by means of X-ray diffraction topography employing white synchrotron beam, high-resolution diffraction (HRD) and photoelectron spectroscopy (XPS) techniques. Topographic investigations show that the crystal is composed of two blocks disoriented by about 1.5° and separated by a narrow deformed region. Some contrasts observed within the crystal volume may be attributed to glide bands and sector boundaries. The contrasts appearing in the vicinity of the surface may be interpreted as due to the presence of small inclusions. The HRD study indicates, in particular, that among point defects, the vacancy type defects dominate and that the density of other defects is small in comparison. The XPS measurements enabled, despite highly insulating properties of the studied crystal, an analysis of its bulk electronic structure, including the main core-levels (O 1s, V 2p, Lu 4/) as well as the valence band range.