Gnanasekar, K. I. ; Tamhane, A. S. ; Pinto, R. ; Nagarajan, R. ; Sharon, M. ; Gupta, L. C. ; Vijayaraghavan, R.
(1994)
*Superconductivity and valence states of Ce, Pr and Tb in bulk Lu _{1−x}M_{x}Ba_{2}Cu_{3}O_{7−δ} (M = Ce, Pr and Tb) systems*
Physica C: Superconductivity, 219
(1-2).
pp. 183-190.
ISSN 0921-4534

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Official URL: http://www.sciencedirect.com/science/article/pii/0...

Related URL: http://dx.doi.org/10.1016/0921-4534(94)90032-9

## Abstract

Bulk samples of composition Lu_{1−x}M_{x}Ba_{2}Cu_{3}O_{7−δ} (M=Ce, Pr and Tb) are examined with respect to the formation of 1-2-3 phase and the superconducting properties. Samples with M = Pr and Tb form a superconducting 1-2-3 phase for values of x≤0.6. We observe that in case of M = Tb, the zero-resistance transition temperature, T_{c(0)}, is 85-86 K and independent of x for 0.1 ≤x ≤0.3. For M = Pr, a maximum T_{c(0)} of 86 K is observed for x=0.1. T_{c(0)} decreases with increasing x for x > 0.1 and the sample with x=0.6 is observed to be semiconducting down to 12 K. With M = Ce, samples of the composition Lu_{1−x−y}Ce_{x}Ca_{y}Ba_{2}Cu_{3} O_{7−δ} form the superconducting 1-2-3 phase for x, Y=0.1 and 0.15. Samples of the compositions Lu_{1−x−y}Pr_{x}Ca_{y}Ba_{2}Cu_{3} O_{7−δ} with x=0.1, 0.2, 0.3 and y=0.1, have lower T_{c(0)}'s than samples of a corresponding Pr content without Ca. We infer from our studies that the Pr ions are in the 3+ valence state for 0.1≤x≤0.3, the Tb ions are mainly in the 3+ valence state for 0.1≤x≤0.3, and the Ce ions are in the 4+ state.

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ID Code: | 61833 |

Deposited On: | 15 Sep 2011 11:56 |

Last Modified: | 10 Jul 2012 08:33 |

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