Please use this identifier to cite or link to this item: http://lib.jncasr.ac.in:8080/jspui/handle/10572/1125
Title: Structure and superconducting properties of Tl1-yPbyY1-xCaxSr2Cu2O7 Dependence of Tc on hole concentration
Authors: Vijayaraghavan, R
Rangavittal, N
Kulkarni, G U
Grantscharova, Emilia
Row, T N Guru
Rao, C N R
Keywords: Oxide Superconductors
Crystal Structure
Temperature
Element
Lead
Pb
Issue Date: 15-Aug-1991
Publisher: Elsevier Science BV
Citation: Physica C 179(1-3), 183-190 (1991)
Abstract: Structure and superconducting properties of Tl1-yPb(y)Y1-xCa(x)Sr2Cu2O7 (y = 0.0, 0.1, 0.25 and 0.5), derived from the parent insulator TlYSr2Cu2O7, have been investigated for different values of x. XANES studies show Pb to be in the 4+ state while Tl is in the 3+ state, suggesting thereby that in this series, (x-y) approximately corresponds to the hole concentration. The in-plane Cu-O distance decreases with increase in x for all values of y. The apical Cu-O distance as well as the Tl(Pb)-O(2) distance show anomalies at x = 0.5 in the series with y = 0.25; at this composition, T(c) also reaches a maximum. In general, the composition (value of x) at which the T(c) of Tl1-yPb(y)Y1-xCa(x)Sr2Cu2O7 reaches a maximum depends on the Pb content and the maximum T(c) itself increases with increase in y, reaching a value of 105 K at y = 0.5. More interestingly, a maximum T(c) occurs at an (x-y) value of approximately 0.25, which is close to the hole concentration at maximum T(c) in other cuprate superconductors containing two CuO2 layers.
Description: Restricted Access
URI: http://hdl.handle.net/10572/1125
Other Identifiers: 0921-4534
Appears in Collections:Research Papers (Prof. C.N.R. Rao)

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