Synthesis of Long and Short Period Bi-Ca-Sr-Cu Oxides

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Abstract
Partial phase diagram of the BiO1.5, (Ca, Sr)O and CuO pseudoternary system at 1133 K has been determined by the X-ray diffraction method. The chemical composition range where the c∼30 Å (T c∼80 K) phase becomes stable has been found in the vicinities of the metal ratio Bi/(Ca, Sr)/Cu between 2/3/2 and 2/2/3. A unique metal ratio 5/8/8 suitable for the c∼36 Å (T c∼110 K) phase is found. A pellet, in which 85 volume % of it showed the diamagnetism at 4 K and the volume ratio of the high-T c phase vs low-T c phase was about 6/1, was synthesized by the firing at about 1148 K and following annealing at 1143, 1123 and 773 K.