| Autor: | M. Schneider, U. Escher, B. Kluge, A. Gladun, C. Köckert, S. Sahling, S. Abens |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Superconductivity
Materials science Condensed matter physics Relaxation (NMR) Thermodynamics Grüneisen parameter Condensed Matter Physics Atomic and Molecular Physics and Optics Thermal expansion Tunnel effect Condensed Matter::Superconductivity Thermal General Materials Science Constant (mathematics) Quantum tunnelling |
| Zdroj: | Journal of Low Temperature Physics. 124:477-495 |
| ISSN: | 0022-2291 |
| DOI: | 10.1023/a:1017575203387 |
| Popis: | Glasslike anomalies of low-temperature thermal properties were observed for the polycrystalline Nb37Ti63 alloy and Nb37Ti63 doped with deuterium. A giant heat release effect was found in (Nb-Ti)92D8 corresponding to a spectral density of two level systems of 7.8·1045 J−1 m−3. After rapid cooling of the sample a length relaxation with a quadratic dependence on the starting temperature was detected obeying a logarithmic time dependence. The results fit to the standard tunneling model assuming a temperature and time independent Gruneisen parameter. A constant Gruneisen parameter is compatible with a constant deformation potential γ but requires ∂λ/∂V to depend on Δ/Δ0. For both systems the thermal expansion coefficient exhibits a linear temperature term in the superconducting state dominating below 1 K. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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