Transition to an Insulator from a Superconductor due to Substitution of Ca by Rare-earth Elements in Bi4Sr4RE2Cu4O16+δ (RE=Nd, Eu, Y)
- 1 May 1988
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 27 (5A) , L790
- https://doi.org/10.1143/jjap.27.l790
Abstract
X-ray diffraction analyses and electrical properties were determined for Bi4Sr4RE2Cu4O16+δ, where RE=Nd, Eu and Y. Samples sintered at 920°C showed identical XRD patterns with that of superconducting Bi4Sr4Ca2Cu4O16+δ, however, their electrical properties were insulating. Oxygen content for the Y-substituted sample Bi4Sr4Y2Cu4O y was y=16.75 and the Cu average valence was 1.875. The compounds seem to correspond to the ground state of Bi4Sr4Ca2Cu4O16+δ, where no holes are doped in Cu-O levels, equivalent to the reduced semiconductor REBa2Cu3O6 in REBa2Cu3O7-δ systems.Keywords
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