Laboratory for Advanced Structural Studies

Wigner Research Centre for Physics • Institute for Solid State Physics and Optics


X-Ray Laboratory

The main line of its research is the study of the atomic structure of solids. Several methods are used depending on the form of the samples and the parameters to be determined. The laboratory is equiped for the study of single crystals, powders and thin layers.

Single crystals (characteristic size ~0.1 mm) are measured by single crystal diffraction technique. This allows the determination of the atomic or molecular structure unknown subtances. There is a possibility to measure at non ambient conditions (25-300 K and max. 50 Kbar).

Powders (individual crystallites tipically have less than 1 mikron diameter) are measured by x-ray powder diffraction. More than 1 mg powder is necessary to take a good quality pattern. There is a possibility to measure as a function of temperature (100-1000 K ). The concentration of known phases can be determined from powder data.

Thin layer samples have large, smooth and flat surface. They can be composed of a single or a multilayer on a substrat. Layer thickness (in the range of 5-100 nm), periodicity (in the range of 5-50 nm) and surface/layer roughness can be determined.

Beside these traditional methods the group is working on the development of new techniques for structure determination. In the last few years two methods, the nuclear resonant scattering of gamma rays from powders, and the atomic resolution x-ray holography were developed. T he first one can be used to study the relation of hyperfine fields and crytal structures in powdered samples containing Mössbauer isotopes. The x-ray holography gives information on the local atomic environment of selected elements in three dimensions. The application of the above methods are not wide spread yet. Further theoretical and experimental work is necessary to implement them in commertial equipments.

Most important fields of research: Structural study of fullerenes, nuclear scattering, x-ray holography.