Syntheses and Properties of the High-Tc Superconductive Bi2-xMoxSr2Ca2Cu3Oy System

摘要

The superconducting properties have been studied for high-Tc superconductors of the Bi2-xMoxSr2Ca2Cu3Oy system (x = 0.03-0.30). The crystal structure is pseudo tetragonal with the average lattice parameters a = 5.38 ∈, b = 5.44 ∈ and c = 30.6 ∈. All samples exhibit superconductivity with Tc offset at 79 K and Tc onset at 90-115 K. The Tc onset point decreases with increasing x, but the Tc offset points are nearly the same for all samples. Scanning electron micrographs show a special growth behavior of the grains with a plate shape. It is suggested that the decrease in Tc onset points with substitution of Mo for Bi is due to the decrease in lattice parameters and to the p-orbital of Mo. It is concluded that Mo does not play a crucial role in the superconducting transition of the Bi2Sr2Ca2Cu3Oy system.