The crystal structure of the La1.6Sr0.4CaCu2O6±δ superconductor has been determined by neutron diffraction powder profile refinement at room temperature on a slightly oxygen deficient sample (δ=-0.06, Tc=55 K). The crystal structure is very similar to that of the nonsuperconducting host compound La1.9Ca1.1Cu2O6-δ. Sr substitutes on the nine coordinate La sites, and there may be some La/Ca mixing on the eight coordinate metal site between the CuO2 planes. Oxygen deficiency occurs in the apical oxygen sites. The compound has the tetragonal symmetry characteristic of a square CuO2 plane at room temperature and 10 K, making it differ from the single-layer analog (La, Sr)2CuO4 which has a buckled, distorted CuO2 plane in the superconducting state.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering