Low-temperature ultrasonic velocity measurements in Na-alumina
- 15 April 1980
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 21 (8) , 3721-3724
- https://doi.org/10.1103/physrevb.21.3721
Abstract
The velocity of 1-GHz longitudinal acoustic waves has been measured in single-crystal Na -alumina at low temperature. The temperature dependence is logarithmic in the range 0.1-5 K. This behavior, previously observed only in amorphous materials, is explained in terms of the two-level systems with a broad distribution of energy-level splittings. A value for the two-level-system acoustic-phonon coupling constant is deduced from the data.
Keywords
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