Research topics

 

The staff at the Institute of Crystallography does research on crystal structures using neutron and x-ray radiation under the guidance of Professor Georg Roth. The goals include a further development of diffraction and scattering methods as well as an application of these methods to elucidate structure-property relationships in modern materials.

Research focus

  • Neutron diffraction
  • Basic research on functional materials
  • Materials synthesis and crystal growth

Selected research projects

  • Single-crystal neutron diffractometer HEiDi at FRM-II in Garching
  • Single-crystal neutron diffractometer POLI at FRM-II in Garching
  • High-pressure crystallography
  • Multiferroics
  • Magnetocalorics
  • Crystal structures of polymers
  • Radioactive waste ceramics
  • Crystal growth
  • Order-disorder phenomena
  • Aperiodic structures
  • Structure-mechanical response correlations of elastic molecular crystals as function of temperature, pressure and uniaxial strain
 

Selected research projects

 

Single-crystal neutron diffractometer HEiDi at FRM-II in Garching

Detailed information are only available in German .

  Copyright: IfK

Single-crystal neutron diffractometer POLI at FRM-II in Garching

Detailed information are only available in German .

  Copyright: IfK

High pressure crystallography

Detailed information are only available in German .

 

Multiferroics

Detailed information are only available in German .

  Copyright: IfK

Magnetocalorics

Detailed information are only available in German .

  Copyright: IfK

Crystal structures of polymers

Detailed information are only available in German .

 

Radioactive waste ceramics

Detailed information are only available in German .

  Copyright: IfK

Crystal growth

Detailed information are only available in German .

 

Order-disorder phenomena

Detailed information are only available in German .

  Copyright: IfK

Aperiodic structures

Detailed information are only available in German .

  Scheme plastic/elastic bending Copyright: IFK

Structure-mechanical response correlations of elastic molecular crystals as function of temperature, pressure and uniaxial strain

Discovery of bending, twisting and shape recovery in molecular crystals in the last 15 years has not only raised eyebrows but generated tremendous interest amongst scientists. The different kinds of macroscopic flexibilities have been successfully obtained in materials where weak intermolecular interactions dominate the crystal packing. Recent discoveries of wave-guide, piezoelectricity, ferroelectricity and magnetic properties in crystals coupled with macroscopic flexibility showcases the immense potential of such crystals for optoelectronic, stress-dissipative and flexible memory applications. However, the limits of mechanical adaptability and their relation to the underlying geometry and energy of the intermolecular interactions remains elusive. The aim of this proposal is to investigate the dependence of intra- and intermolecular interactions within crystals as function of temperature, pressure and uniaxial stress. Within the framework of the project, three model systems viz. a brittle crystal, an elastically and an elasto-plastic crystal shall be studied. At non-ambient temperature, elevated pressure using diamond anvil cells and uniaxial strain, powder and single crystal X-ray and neutron diffraction experiments will be performed to obtain accurate information about positions and displacement parameters of atoms including hydrogens. Systemic analysis of variation of arrangement and energy of intermolecular interactions will be performed as a function of non-ambient temperature and pressure. Successful conclusion of the project will decipher the structure-mechanical response correlations of molecular crystals in general which will be seed to further design of flexible crystals.