The (Bi,Pb)4Sr3Ca3Cu4O glass–ceramics: Disordered metal and superconductor

The (Bi 0.8 Pb 0.2 ) 4 Sr 3 Ca 3 Cu 4 O x glass, annealed under proper conditions, is transformed into a granular metal and superconductor. Oxide superconductors of the bismuth family crystallize as a result of annealing: (Bi,Pb) 2 Sr 2 CuO x (2201, T c = 10 K), (Bi,Pb) 2 Sr 2 CaCu 2 O x (2212, T c = 85 K) and (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O x (2223, T c = 100 K). (Bi 0.8 Pb 0.2 ) 4 Sr 3 Ca 3 Cu 4 O x glass-ceramic samples were obtained by annealing an amorphous solid at temperatures between 650 °C and 870 °C. The temperature dependence of resistivity in annealed samples was measured with the conventional four-terminal method in the temperature range from 3 K to 300 K. The (Bi 0.8 Pb 0.2 ) 4 Sr 3 -Ca 3 Cu 4 O x glass-ceramics may be considered as a disordered metal and superconductor. The material has high resistivity and a high, usually negative, temperature coefficient of resistivity (TCR). Its granular and disordered character is also reflected in its superconducting properties. The normal-state and superconducting properties are correlated.