Weak-Link-Induced Thermoelectricity in U-Shaped BSCCO Superconductor
| Autor: | R. A. Doyle, V. V. Gridin |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Superconductivity
Materials science High-temperature superconductivity Condensed matter physics General Physics and Astronomy law.invention Temperature gradient law Electrical resistivity and conductivity Condensed Matter::Superconductivity Seebeck coefficient Thermoelectric effect Equipotential Current (fluid) |
| Zdroj: | Europhysics Letters (EPL). 19:423-428 |
| ISSN: | 1286-4854 0295-5075 |
| DOI: | 10.1209/0295-5075/19/5/013 |
| Popis: | The recently reported weak-link-induced analogue of the Fountain effect in high-Tc superconductors (Europhys. Lett., 13 (1990) 175) involves measurement of the response of a micro-bridge-shaped sample to superimposed electrical and thermal gradients. This geometry is however asymmetric since the current contacts are always at different temperatures. Consequently doubts might be expressed about the interference of Peltier effects at the current contacts with the measured symmetry in the I-V characteristics of the sample. We have studied the temperature dependence of the voltage response of U-shaped samples of polycrystalline BSCCO 2212 superconductor in the presence of a parallel applied temperature gradient and applied current when the current direction is reversed. It is shown that this method is directly complementary to the measurement of asymmetry in critical current density by use of I-V characteristics at fixed temperature. The U-shaped geometry employed here allows the current electrodes to be held equipotential and at the same temperature. Our results show that the Fountain effect, which is due to supercurrent-induced phase differences across weak links in the sample, is apparent in this material when measured using the U-shaped geometry. This provides further support for the importance of weak-link-related thermoelectric effects in high-temperature superconductors. |
| Databáze: | OpenAIRE |
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