Hamburg 2001 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
DY: Dynamik und Statistische Physik
DY 53: Gl
äser III
DY 53.1: Talk
Friday, March 30, 2001, 11:30–11:45, S 7
Network Modification, Structural Relaxation and the Boson Peak — •J.- B. Suck1, H. Uhlig1, S. Mentese1, and S. Longeville2 — 1TU-Chemnitz, Institute of Physics, Materials Research and Liquids, 09107 Chemnitz, Germany — 2Hahn-Meitner-Institute, Glienickerstr.100, 10 Berlin, Germany
Introduction of Li2O into SiO2 glass modifies the SiO2 network by breaking up the network of the strong rings of SiO4 tetrahedra [1]. This modification leads to a weakening of the network structure and a subsequent structural relaxation which results in a densification of the amorphous structure by more than 5 per cent. As a consequence, the network loses some of its free volume formed by adjacent sixfold rings.
We have studied the consequences of this process on the Boson peak in the spectra of Li2Si2O5 glass using neutron inelastic scattering techniques. The experiment was performed at 296K with an incident energy of 4 meV at the cold neutron time-of-flight spectrometer NEAT at the reactor of the HMI, Berlin. We find a strong influence on the atomic dynamics of the modified network in the energy region of the Boson Peak, which allows us to interpret the observed phenomena in the framwork of different kinds of modes which contribute to different energy regions in these spectra.
[1] H.Uhlig et al., Am. Cer. Soc. 79 (1996) 2833