| Numéro |
J. Phys. Colloques
Volume 41, Numéro C8, Août 1980
Fourth International Conference on Liquid and Amorphous Metals
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|---|---|---|
| Page(s) | C8-751 - C8-753 | |
| DOI | https://doi.org/10.1051/jphyscol:19808187 | |
J. Phys. Colloques 41 (1980) C8-751-C8-753
DOI: 10.1051/jphyscol:19808187
ULTRASONIC AND SPECIFIC HEAT MEASUREMENTS IN QUENCHED SUPERCONDUCTING NbZr
N. Thomas1, W. Arnold2, E. Gmelin1, K. Guckelsberger1, G. Weiss1 et H.v. Löhneysen31 Max-Planck-Institut für Festkörperforschung, D-7000 Stuttgart 80, R.F.A.
2 Brown Boveri Research Center, CH-5405 Baden-Dätttwil, Switzerland
3 Physikalisches Institut der RWTH, D-5100 Aachen, R.F.A.
Abstract
In crystalline NbZr the quenching process is known to create a partially amorphous phase containing tunnelling states whose thermal behaviour resembles that of other amorphous materials. In order to study the interaction of the tunnelling states with electrons we have carried out ultra-sonic measurements with longitudinal waves at 30 and at 90 MHz. The absorption does not decrease at the superconducting transition (Tc = 8.6 K) - as expected for crystalline superconductors - but at temperatures well below Tc. Specific heat measurements on the same specimen demonstrate that nevertheless the whole sample becomes superconducting at Tc. In our view the recent theory by Black and Fulde on the interaction between electrons and tunnelling states can account for our observations.