Photon Science Colloquium: Good Vibrations in Functional Materials

by Raphael P. Hermann (Forschungszentrum Jülich GmbH, Germany
Faculté des Sciences, Université de Liège, Belgium)

Friday, April 8, 2011 from to (Europe/Berlin)
at Bldg. 28c, seminar room
Description Good Vibrations in Functional Materials
meV Resolved Nuclear Resonance Scattering above 30 keV

R. P. Hermann Jülich Centre for Neutron Science, JNCS, Peter-Grünberg Institut, PGI, JARA-FIT, Forschungszentrum Jülich GmbH, Germany
Faculté des Sciences, Université de Liège, Belgium

Our society has increasing requirements for energy and information processing technologies and functional materials are at the base of such technology. Both in thermoelectric materials used for direct conversion of heat to electricity and phase change materials used in read-write optical memories, the lattice dynamics plays an important role. Nuclear inelastic scattering is a powerful method to access the vibrational properties of Sb and Te, key elements for many of these materials. Owing to tremendous progress in x-ray monochromatization above 30 keV, it is now possible to obtain nuclear inelastic scattering spectra for these elements with ~1 meV resolution. Access to unique aspects of the lattice dynamics in thin films, nanowires, and nanoinclusions in complex matrices is thus open. The ESRF is acknowledged for provision of synchrotron radiation at ID18 and ID22N and I am greatly indebted to I. Sergeev, H.-C. Wille, Yu. Shvyd'ko, D. Bessas, P. Bauer Pereira, T. Claudio Weber, and A. Möchel, for the fruitful collaboration during the experimental work.

Raphael Hermann graduated 2004 at the Université de Liège with a work about neutron scattering from thermoelectic and magnetic materials. He is currently a Junior Group Leader of a Helmholtz Young Investigator Group 'Lattice Dynamics in Emerging Functional Materials' at the Jülich Centre for Neutron Science.