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M: Metallphysik
M 3: Wasserstoff in Metallen
M 3.2: Vortrag
Montag, 8. März 2004, 10:30–10:45, H4
Raman spectroscopy on β-YH2+δ and β-YD2+δ thin films — •A.-M. Carsteanu, M. Rode, D. Zur, A. Borgschulte, H. Schröter, and J. Schoenes — Institut für Halbleiterphysik und Optik, TU Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig, Germany
The hydrides of yttrium and other rare-earth metals have been the subject of increasing research due to their switchable optical properties. The metal insulator transition of Y films grown on (111) CaF2 substrates and capped with Pd is monitored using Raman spectroscopy. In the β phase of YH2+δ and YD2+δ we find changes in the spectra, showing the existence of a new intermediate phase. The new spectrum is also observed for an in situ grown YH2+δ film. An analysis of the factor group of this system indicates that the intermediate phase has the I4/mmm structure. Temperature dependent measurements point to a short-range ordering of the hydrogen sublattice above 150 K.