The concentration dependence of the transition temperature Tc and microstructure has been studied in the high-Tc compounds Y1-2xBa2-0.2xKxCu3O7-y, Y1Ba2Cu3.5-xKxO7-y, Y1Ba2-xCu3KxO7-y, where x = 0-1.50. Only traces of K (1 × 10-2 wt%) were observed in all samples after the final baking and no proof could be found for alkali metal cations participating in the Perovskite crystal cell. Between x = 0.40-0.75 a homogeneous grain-size ceramic structure was observed. This behaviour permits the obtaining of monophase Y1Ba2Cu3Oy with values of Tc = 93.6 K and ΔT = 1.5 K using simplified technological process and baking in air atmosphere.
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