Sr2(Gd,Ce)2Cu2RuO10 synthesized by a new -type solid-state reaction in the presence of oxygen-water vapor mixed atmosphere and its electric properti es

Sr_Ru cuprates synthesized via traditional solid_state reaction is always accompanied by the formation of small amounts of SrRuO3 impurity phase with ferromagnetism. In this paper we report that not only the pure phase compound Sr2 GdR uO6 without any ferromagnetic SrRuO3 impurity phase is suc cessfully prepared by means of a new_type reaction of solid state in presence of O2 (or air)_wat er vapor mixed atmosphere，but also RuSr2(Gd,Ce)2Cu2O10(Ru_1222）wit hout any ferromagnetic SrRuO3 impurity phase is further synthesized u nder a re lative low reactive temperature when the Sr2GdRuO6 is used as a precursor. T he authors discuss the formation of the product Sr2GdRuO6 and mechanism of t he new_type reaction of solid state in presence of water vapor in detail. In add ition, the effects of SrRuO3 impurity phase on the electric propertie s of the product Ru Sr2(Gd,Ce)2Cu2O10 is also discussed. It suggests that the water vapor for the new_type solid_state reaction is not beneficial to the tran sformation of SrRuO3 to Sr2GdRuO6, and it is to suppress the formation of SrRuO3 due to the formation of RuO2·nH2O. Thus the amount of SrRuO3 impurity phase in Ru_1222 phase is controlled in the reaction of solid state. I t seems that the presence of a small amount of SrRuO3 impurity phase is favourable for making the Ru_1222 phase superconductive.