Copper isotope shifts in Pr and La substituted 123 and 124 cuprate superconductors; comparison with oxygen isotope shifts

Morris, D. E. ; Sinha, A. P. B. ; Kirtikar, V. ; Inyushkin, A. V. (1998) Copper isotope shifts in Pr and La substituted 123 and 124 cuprate superconductors; comparison with oxygen isotope shifts Physica C: Superconductivity, 298 (3-4). pp. 203-208. ISSN 0921-4534

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S09214...

Related URL: http://dx.doi.org/10.1016/S0921-4534(97)01730-9

Abstract

Copper isotope shifts of Tchave been measured in 123 and 124 cuprate superconductors with partial substitutions by Pr and La to reduce hole concentration. The 123 compositions were PrxY1-xBa2Cu3O7 (x=0.2, 0.3, 0.4) and YLa0.3Ba1.7Cu3O7. The 124 compounds were PrxY1−xBa2Cu4O8 (x=0.2, 0.3) and YLa0.3Ba1.7Cu4O8.Oxygen isotope experiments in materials with these compositions have shown substantial isotope shifts. We find that the Cu isotope shifts are also substantial, but somewhat smaller. Other findings are: (1) the Cu isotope exponent αCu is positive, (2) αCu increases rapidly as Tc is reduced by substitution, and rises to a substantial fraction of the BCS value, behavior which is similar to that of the oxygen isotope exponent α O, and (3) when Tc is reduced by non-isovalent substitution, both O and Cu isotope shifts increase greatly, but the ratio αCu/αO remains 0.75±0.1 in both 123 and 124, regardless of the amount and site of the non-isovalent substitution.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Superconductivity; Copper Isotope Effect; Pr Substitution; La Substitution
ID Code:48962
Deposited On:19 Jul 2011 07:29
Last Modified:20 Jul 2011 09:52

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