STRUCTURAL STUDY OF THE QUASI-ONE-DIMENSIONAL COMPOUND (Ca1-xYx)0.82CuO2 PREPARED AT ROOM PRESSURE

摘要

A solid solution of the quasi 1-D cuprate, (Ca1-xYx)0.82CuO2 (0 less than or equal to x less than or equal to 0.435), has been successfully synthesized in an O stream at room pressure. Structural changes have been determined for the basic crystal structure by means of the Rietveld method using powder XRD. Upon Y doping, the nearest (intrachain) Cu-Cu distance increases from 1.93 to 1.98 angstroms, while the next-nearest (interchain) Cu-Cu distance decreases from 3.46 to 3.41 angstroms. The incommensurate superstructure, originating from differences in the periodic arrangement of the (Ca,Y) atoms and CuO2 chains, has also been examined. The modulation period along the crystal a axis implies that the stoichiometry of the solid solution shifts toward that of the cation-deficient member (Ca1-xYx)0.80CuO2. This compositional discrepancy might be canceled by the large change in the modulation period along the c axis. 21 refs.