[Zurück]

K. Hense, E. Gratz, A. Lindbaum, H. Nowotny, A. Hoser, F. Güthoff, J. Klenke:
"Lattice dynamics in YCu₂";
Poster: 52. Jahrestagung der ÖPG, Leoben; 23.09.2002 - 26.09.2002.

The lattice dynamics of the orthorhombic YCu2 compound has been studied by inelastic neutron experiments
on a single crystal in Juelich (UNIDAS spectrometer) and at HMI (E1 spectrometer). An axial
symmetric Born- von Karman model with ten springs was used for the fit the neutron data. Ab-initio calculations
at the _-point provided important information to start the Born- von Karman fit procedure. The
thus obtained phonon dispersion relation was checked by a comparison of the calculated phonon density
of states (PDOS) based on the Born- von Karman fit with the measured PDOS deduced from time-of-flight
experiments (LRMECS spectrometer, Argonne). Good agreement was found among both data sets. From
the PDOS the lattice contribution to the specific heat was calculated which corresponds well with the experimental
specific heat data. A comparison of elastic constant measurement with the initial slope of the
acoustic phonon branches was done. The lattice dynamics of YCu2, is representative for the other RCu2
compounds. This knowledge will be helpful for further studies such as crystal field-phonon interaction or
the magnon-phonon interaction in this family of orthorhombic compounds.