(14-x)SrCO3-xCaCO3-24CuO system to synthesize spin-ladder compounds Sr14-xCaxCu24O41 using DTA and XRD techniques

The (14 - x) SrCO3-xCaCO(3)-24CuO system was investigated by means of differential thermal analysis (DTA) technique combined with the powder X-ray diffraction (XRD) technique, and the relationship of its thermal behavior with the synthesis of spin-ladder compound Sr14-xCaxCu24O41 was first analyzed in detail. It is found that the DTA curve (x <= 5.6) exhibits two endothermic peaks and could be divided into three reaction stages, corresponding to the solid state reaction to synthesize single-phase Sr14-xCaxCu24O41. The DTA curve (x >= 8.4) shows three big endothermic peaks below 1000 degrees C. The intensity and the position of the first endothermic peak around 800 degrees C is depending on the content of CaCO3 in the system, while the third endothermic peak is the crucial factor of the synthesis of single-phase compound.