Effect of lead substitution in bismuth-based cuprate systems containing both low-Tcand high-Tcphases
| Autor: | Deepak Varandani, Nirupa Sen, E. Gmelin, V. P. S. Awana, B. V. Kumaraswamy, Abhijit Bandyopadhyay, A. V. Narlikar |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Physical Review B. 48:6470-6476 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.48.6470 |
| Popis: | We report the results of resistivity, ac-susceptibility, and specific-heat measurements carried out on samples of ${\mathrm{Bi}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Pb}}_{\mathit{x}}$${\mathrm{Sr}}_{2}$${\mathrm{Ca}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{10+\mathit{x}}$ (0\ensuremath{\le}x\ensuremath{\le}0.7) that were characterized by x-ray diffraction and high-resolution scanning tunneling microscopy. The zero resistance temperature, ${\mathit{T}}_{\mathit{c}}$ (R=0), shows a peak at x=0.3 and the susceptibility data indicate that although a high-${\mathit{T}}_{\mathit{c}}$ 2:2:2:3 phase is present at 110 K, there is a second transition at 90 K that seems to indicate the existence of an additional low-${\mathit{T}}_{\mathit{c}}$ 2:1:2:2 phase. The specific-heat data unambiguously indicate a clear and distinct anomaly around ${\mathit{T}}_{\mathit{c}}$ for samples with x=0.3--0.4 and smearing of the anomaly for xg0.5. Based on the results obtained from these combinations of experiments, the role of lead substitution in Bi samples, particularly in the stabilization of the 2:2:2:3 phase has been discussed. |
| Databáze: | OpenAIRE |
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