The investigation of critical temperature $T_c$ of homophase superconductors Bi$_{1.7}$Pb$_{0.3}$Sr$_{2}$Ca$_{(n-1)}$Cu$_{n}$ O$_{y}$ ($n$ = 3, 4, 5) and current–voltage characteristics of inp semiconductor–Bi/Pb superconductor (2223, 2234, 2245) sandwich pairs

The electrophysical properties of semiconductor–superconductor sandwich pairs (InP–Bi/Pb 2223, 2234, 2245) are investigated, in which homophase superconductors based on bismuth cuprates with high reproducible critical temperatures of superconducting transition $T_c$ = 107–180 K are used. The advantage of melt solar technology for obtaining superconducting materials is demonstrated. The microstructure and phase composition of strongly anisotropic superconductors with nominal composition Bi$_{1.7}$Pb$_{0.3}$Sr$_{2}$Ca$_{(n-1)}$Cu$_{n}$ O$_{y}$ ($n$ = 3, 4, 5) are researched. A technique of experimental determination of superconducting transition critical temperatures $T_c$ in single-phase and homophase HTSC samples is presented. The current–voltage characteristics of InP–Bi/Pb pairs are investigated. The relationship between the electrical resistance of sandwich pairs and superconductor critical temperature $T_c$ is established.