Is non-stoichiometric crystalline Na β-alumina an ideal amorphous material ? An ultrasonic answer
Open Access
- 1 January 1980
- journal article
- Published by EDP Sciences in Journal de Physique Lettres
- Vol. 41 (3) , 65-68
- https://doi.org/10.1051/jphyslet:0198000410306500
Abstract
We report the results of ultrasonic attenuation and velocity measurements in the 1 GHz range in Na β-alumina and in the temperature domain 2-80 K. We observed two different behaviours for the attenuation, one varying as ω0 T3 at low temperature, the other as ω T0 at high temperature. The velocity goes through a maximum and then decreases linearly with the temperature. These results are found to be in good agreement with the predictions of the theory of two-level systems developed for amorphous materials. In that sense β-alumina appears to be an ideal amorphous materialKeywords
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