Specific-heat anomaly of overdopedBi1.8Pb0.3Sr1.9CuOy
| Autor: | Kazuhiko Yamaya, H. Mayama, Yoshitoshi Okajima |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | Physical Review B. 57:14470-14475 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.57.14470 |
| Popis: | The temperature dependence of the specific heat of ${\mathrm{Bi}}_{1.8}{\mathrm{Pb}}_{0.3}{\mathrm{Sr}}_{1.9}{\mathrm{CuO}}_{y}$ samples in the overdoped region has been measured between 1.5 and 8 K. Specific-heat anomalies were observed at ${T}_{c}$ in two superconducting samples, while no anomalies were observed in a nonsuperconducting one. The values of $\ensuremath{\Delta}C/\ensuremath{\gamma}{T}_{c}$ were quite small in comparison to the BCS value, and the electronic specific heat in the superconducting state near ${T}_{c}$ exhibited a weak temperature dependence. These findings are consistent with the impurity effects predicted by the model of $d$-wave superconductors proposed by Sun and Maki. Furthermore, we found that the Sommerfeld constant \ensuremath{\gamma} increases with increasing doped carrier from the superconducting region to the normal metal region, in contrast to the case of ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4}.$ |
| Databáze: | OpenAIRE |
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