Solid solution formation in the new cuprate system (Sr, K)(1-x)(Ca, Na)(x)CuO2 +/- z (0 <= x <= 0.5)

Synthesis and some experimental results of the new cuprate system (Sr, K)(1 -K)(Ca, Na)(x)CuO2+/-z(0.0 less than or equal to n less than or equal to 1. 0) are reported for the first time. We prepared a series of polycrystalline samples of this system with x-steps of 0.1, by solid-state reaction method in air at ambient pressure below melt temperature. It is observed the form ation of a solid solution in the range 0 less than or equal to x less than or equal to 0.5 at 750 degrees C. The characterization of the samples by X- ray powder diffraction indicates that the single phase is isostructural to the one for Cu2SrO3 compound, reported in the JCPDS-International Center fo r Diffraction Data (ICDD) file No. 39-0250, which has an orthorhombic unit cell. The compositions in the range 0.6 less than or equal to x less than o r equal to 1.0 have an unknown phase and CuO. Further characterization stud ies by scanning electron microscopy, thermogravimetric and differential the rmal analysis are shown. (C) 1999 Elsevier Science Ltd. All rights reserved .