Professur Röntgen- und Neutronendiffraktometrie






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Research profile

The main direction of research work is the investigation of the static atomic structure of condensed matter by diffraction methods. X-ray and neutron diffraction are employed for studying

  • the atomic arrangement in non-crystalline materials, especially in molten elements and alloys,
  • the atomic structure of of thin films (phase analysis, texture, strain and stress),
  • phase transitions (separation of immiscible binary and ternary liquid alloys, supercooled melts and solidification, metastable crystalline films).

X-ray reflectometry is used for the determination of thickness, density, density-profiles and interfacial roughness in both buried and surface thin films.

In addition density, viscosity, surface tension and interfacial tension are measured in the liquid state up to elevated temperatures. These properties have direct practical importance, and play a crucial role in the verification of models describing the liquid phase, and of demixing and solidification processes.

In the X-ray laboratory various diffractometers are installed. Investigations in the liquid state are done with horizontal sample surfaces and special high-temperature equipment. Three vertical axis diffractometers (one two-axis and two four-axis) serve for the measurements on crystalline or amorphous bullk materials and thin films.

Neutron experiments have been or are still done at a variety of neutron facilities such as for instance VIK Dubna, HMI Berlin, LLB Saclay, ILL Grenoble, ISIS RAL Chilton and NFL Studsvik. Diffraction experiments on very thin films of weakly scattering atoms are carried out with the help of the diffractometer ROBL at ESRF. Diffraction experiments on amorphous and liquid samples using very hard X-rays from the wiggler-beamline BW5 at HASYLAB became of more importance in last years.

Reverse Monte Carlo Simulations of simultaneously both, X-ray and neutron diffraction data have been proved to be a very useful tool for the determination of partial structure factors.