Lattice dynamics and related diffusion properties of intermetallics: II. Ni sub 3 Sb

The phonon dispersion of the intermetallic Ni sub 72.5 Si sub 27.5 has been studied by inelastic neutron scattering in its high-temperature phase of DO sub 3 structure, stable above 530 deg C. The dispersion has been examined at a temperature of 600 deg C; some selected branches were also studied at...

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Bibliographic Details
Published in:Journal of physics. Condensed matter 1997-11, Vol.9 (46), p.10283-10292
Main Authors: Randl, O G, Petry, W, Vogl, G, Buhrer, W, Hennion, B
Format: Article
Language:English
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Summary:The phonon dispersion of the intermetallic Ni sub 72.5 Si sub 27.5 has been studied by inelastic neutron scattering in its high-temperature phase of DO sub 3 structure, stable above 530 deg C. The dispersion has been examined at a temperature of 600 deg C; some selected branches were also studied at 530 deg C (i.e. very close to the phase transition) and at 900 deg C. In general, the phonons are very strongly damped and some branches have not been found at all. For transverse phonons with [ xi xi 0] propagation, the frequency does not change as a function of the temperature, but the widths become larger towards higher temperatures. The migration enthalpy and several other thermodynamic quantities have been calculated from the densities of states. The anomalous behavior of the alloy is related to high vacancy densities.
ISSN:0953-8984