Fluctuation-induced excess conductivity in the compounds CaREBaCu3O7−y (RE=La and Sm)
- 23 Downloads
The compounds CaREBaCu3O7−y (RE=La and Sm) are tetragonal at room temperature withT c between 60 and 70 K. The single-phase compounds were prepared by solid-state reaction. The resistivity was measured by a four-probe technique in a continuous flow cryostat with the temperature being controlled to an accuracy of 10 mK. The resistivity vs temperature showed a break in slope around 180 K in CaLaBaCu3O7−y and around 220 K in CaSmBaCu3O7−y . The results were analysed for fluctuation conductivity from 180 K downwards. A plot of dρ/dT vsT showed a sharp peak atT m =69·69 K for La compound and 66·00 K for the Sm compound. Detailed analysis of the resistivity in the regionT on to 180 K was carried out using the procedure due to Veira and Vidal. The results are discussed in this paper.
KeywordsHighTc superconductors CaREBaCu3O7−y fluctuation excess conductivity
Unable to display preview. Download preview PDF.
- de Leeuw D M, Mutsaers C A H A, Van Hal H A M, Verweij H, Carim A H and Smoorenberg H C A 1988Physica C156 126Google Scholar
- Hagen S J, Wang Z Z and Ong N P 1988Phys. Rev. B38 7137Google Scholar
- Krishnan H 1990 (unpublished)Google Scholar
- Lawrence W E and Doniach S 1971Proc. XII Int. Conf. Low Temp. Phys. Kyoto (ed.) K Eizo (Tokyo: Keigaku) p. 361Google Scholar
- Peng J L, Klavins P, Shelton R N, Radousky H B, Hahn P A and Bernardez L Constantino 1989Phys. Rev. B39 9074Google Scholar
- Srinivasan R 1990Proc. Int. Conf. High Temp. Superconductivity, Bangalore, India, (and references therein)Google Scholar
- Varadaraju U V, Venkateswara Rao C R, Subba Rao G V, Krishnan H, Srinivasan R, Tomy C V and Malik S K 1990Proc. Int. Conf. High Temp. Superconductivity, Bangalore, India Google Scholar
- Veira J A and Vidal F 1989Physica C159 468Google Scholar