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Struktur und Dynamik Poster: Mi., 14:00–16:30 M-P157
High-frequency dynamics in metallic glasses
Tullio Scopigno 1 , Jens-Boie Suck 2 , Roberta Angelini 1 , Francesco
Albergamo 3 , Giancarlo Ruocco 1
1 INFM CRS-SOFT and Dipartimento di Fisica, Universita´ di Roma La Sapienza,
I-00185, Roma, Italy – 2 Institute of Physics, University of Technology Chemnitz,
D-09107 Chemnitz, Germany – 3 European Synchrotron Radiation Facility, F-38043
Grenoble, Cedex, France
Using inelastic X-ray scattering we studied the collective atomic dynamics in the glassy
alloy Ni33Zr67 in the first pseudo-Brillouin-zone. This energy-, ¯hω, and momentum-, Q,
region is of primary importance for the investigation of collective modes in disordered
systems. For metallic glasses it had not been accessible up to now. Using IXS this
Q-region could now be explored and key properties such as the dispersion of collective
excitations (see Fig. 1) and the damping of the acoustic modes[1] be determined.
We discuss these results in the general context of recently proposed models for the
damping of acoustic modes in glasses. We demonstrate the existence of well defined (in
the Ioffe-Regel sense) acoustic-like excitations also well above the boson peak energy
in this moderately fragile glass and the importance of the Boson peak intensity for the
damping mechanism.
[1] T. Scopigno et al. Phys. Rev. Lett. 96 (2006) 135501
Fig. 1: Dispersion curve