Localized Rattling of Al atoms in VAl10+δ
Abstract
We have studied the localized rattling mode in the ``Einstein solid'' VAl 10+δ using a suite of thermodynamic, transport, and neutron diffraction measurements. The rattling originates from Al atoms that occupy the large void within Z16 Friaf polyhedra, of which there are eight per unit cell in the VAl 10+δ structure. Our heat capacity, thermal expansion, and electrical resistivity data are all qualitatively consistent with a low-frequency harmonic vibration of the atom. However, our neutron diffraction data show that the rattling atom potential is better described as sixth-order, rather than harmonic. Using a single-site, sixth-order effective potential for the rattling atom, we can explain our thermodynamic, transport, and structural data, including the unusual temperature dependence of the elastic constants.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2011
- Bibcode:
- 2011APS..MARL35008S