Oxidation state and superconducting properties of Y1-xPrxSr2Cu2.85Re0.15O7+δ

Murugesan, M. ; Selvam, P. ; Sharon, M. ; Gupta, L. C. ; Pinto, R. ; Rao, M. S. R. ; Gopinath, C. S. ; Subramanian, S. (1996) Oxidation state and superconducting properties of Y1-xPrxSr2Cu2.85Re0.15O7+δ Journal of Applied Physics, 80 (12). pp. 6884-6887. ISSN 0021-8979

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Official URL: http://jap.aip.org/resource/1/japiau/v80/i12/p6884...

Related URL: http://dx.doi.org/10.1063/1.363758


Superconductivity exists in orthorhombic Y1-xPrxSr2Cu2.85Re0.15O7+δ up to a critical concentration (xcr) of 0.65. A progressive decrease in Tc occurs as x increases from 0 to 0.65. A further increase in x leads to a tetragonal transformation and as a consequence the Tc vanishes; however, the orthorhombicity of these Sr-based compounds is much lower than that observed for the Ba analog, Y1-xPrxBa2Cu3O7-δ and, hence, the Tc. On the one hand, crystal chemistry correlations indicate that the Pr ion is in trivalent state while on the other hand, the stabilizing cation, viz., Re, is in hexavalent state which accounts for the excess oxygen (>7.0) in the system. The high xcr value of the Sr series compared to the Ba series (xcr=0.55) is attributed to the much reduced orbital overlap of the trivalent Pr(4f) state with the Cu(3dx2-y2)-O(2p) conduction band, via hole localization and/or pair breaking, and is not due to the much discussed hole filling by tetravalent Pr.

Item Type:Article
Source:Copyright of this article belongs to American Institute of Physics.
Keywords:XRD; High-TC Superconductors; Oxidation; Yttrium Oxides; Praseodymium Oxides; Strontium Oxides; Rhenium Additions; Copper Oxides; Chemical Composition; Transition Temperature; Crystal Structure; X-ray Diffraction
ID Code:61772
Deposited On:15 Sep 2011 12:06
Last Modified:10 Jul 2012 08:55

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