Vrije Universiteit, Amsterdam, The Netherlands

The Condensed Matter Physics Department, Faculty of Science, Vrije Universiteit Amsterdam, Netherlands, has a long standing experience in the field of transition metal- and rare-earth-hydrogen systems. More than 100 articles have been published about the fundamental properties of hydrogen in transition metals. The greatest achievement was the discovery of the so-called switchable metal-hydride mirrors in 1996 in yttrium and lanthanum-hydrides. These are films that are shiny metallic in absence of hydrogen but become transparent when loaded with hydrogen. This intriguing effect posed many fundamental questions that have been systematically investigated since then. Very recently it became clear that the changes induced by hydrogen in a switchable mirror material could be used for hydrogenography, i.e. the 2-dimensional detection of hydrogen in metal hydrides and the determination of the enthalpy of formation thereof. This opens completely new ways to investigate the hydrogen ab/desorption in new materials. Exploring the benefits of this technique on well-known Mg2NiH4, it immediately showed the remarkable compositional dependence of the kinetics of hydrogen storage in this material. In addition, certain Mg-based switchable mirrors exhibit a strongly absorbing black-state at intermediate hydrogen compositions between the shiny metallic and transparent state. This black state offers interesting possibilities for technological applications in smart solar collectors and fiber optic hydrogen sensors.

Dr. Bernard Dam is an expert in thin film growth and characterization. He obtained his PhD in 1986 at the Radboud University in Nijmegen. After 6 years he left Philips Research Laboratories in 1992 and is now Associate Professor in the Condensed Matter group headed by Prof. R. Griessen. He coordinates the thin film and characterization activities including MBE, PLD, Sputtering, AFM, STM, RBS and High-Resolution X-Ray diffraction. Thin film work comprises, metal multilayers, (High-Tc) oxide thin films and metal(-hydrides). His focus is on the application of metal-hydrides for sustainability. Apart from the search for new light-weight metal hydrides for storage applications, this implies the development of switchable devices for the development of smart windows and the development of optical fiber hydrogen sensors. He has (co-) authored over 130 scientific papers.

Prof. Ronald Griessen (head) is an internationally recognized expert in science and technology of hydrogen, in particular in Hydrogen Switchable mirrors. He studied physics and Mathematics at the Swiss Federal Institute of Technology (ETH) in Zürich (Switzerland) and obtained his PhD in physics on the basis of his work on Quantum oscillatory effects in simple metals. From 1974 till 1976 he was research associate at the McLennan Physical Laboratory of the University of Toronto, Canada. Since then he is professor of Physics and head of the Condensed Matter Physics department at the Vrije Universiteit in Amsterdam. He has co-authored over 230 scientific papers.  In 2001 R. Griessen was awarded the “Physica Prize” of the Dutch Physical Society for his accomplishments in the field of metal-hydride switchable mirrors.

Experimental facilities: thin film preparation (MBE, sputtering, laser ablation, see picture above), AFM, STM, X-ray-diffraction, RBS, optical spectrometers (UV-VIS, IR), scanning reflection-transmission spectrometer, hydrogenography, UHV-compatible fiber optic spectrometers, van der Pauw resistometry.

D. M. Borsa, A. Baldi,M. Pasturel, H. Schreuders, B. Dam and R. Griessen, P. Vermeulen, P. H. L. Notten, Mg-Ti-H thin films for smart solar collectors, Appl. Phys. Lett. 88, 241910 (2006)

R. Gremaud, A. Borgschulte, C. Chacon, J.L.M. van Mechelen, H. Schreuders, A. Züttel, B. Hjörvarsson, B. Dam and R. Griessen, Structural and optical properties of Mg_xAl_1-xH_y gradient thin films: a combinatorial approach, Appl. Phys. A84, p77-85

J.L.M. van Mechelen, B. Noheda, W. Lohstroh, R.J. Westerwaal, J.H. Rector, B. Dam, and R. Griessen, Mg-Ni-H films as selective coatings: tunable reflectance by layered hydrogenation, Appl. Phys. Lett. 84, 3651 (2004)

Contact:

Dr. Bernard Dam
Vrije Universiteit
Condensed Matter Physics
De Boelelaan 1081
NL-1081 HV  Amsterdam
The Netherlands

Phone +31 (20) 598 - 7917
Fax +31 (20) 598 - 7992

http://www.nat.vu.nl/cond/