In systematic studies of oxygen-deficient Ba2YCu3O7-δ, we have found that a structural anomaly occurs at the composition where bulk superconductivity disappears. The observed step-like increase in the c lattice parameter, when associated with changes in the atomic positions within the unit cell, indicates that superconductivity is lost due to a charge redistribution from the copper-oxygen chains to the copper-oxygen planes. This is microscopic experimental evidence establishing the role of secondary structural elements in the layered copper-oxide high-Tc superconductors.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering