Superconducting properties of Tl1-xYbxBa2Ca2Cu3O9- δ

Abstract

A series of high temperature superconductor samples of type Tl1-xYbxBa2Ca2Cu3O9- δ with x ranging from 0 to 0.5 have been synthesized at 860°C for 4 h. The x-ray powder diffraction and the electrical resistivity measurements for the prepared samples have been reported. X-ray data indicate that the solubility limit xs between Tl3+ and Yb3+ ions in Tl1-xYbxBa2Ca2Cu3O9- δ phase is about 0.3. The transition temperature Tc, determined from the electrical resistivity data, shows a depression in its value with increasing Yb-content. The critical concentration xc, at which the superconductivity disappeared, is estimated to be 0.58. The effect of external magnetic field on the electrical resistivity behaviour has been studied. The activation energy, calculated from these data, shown a decrease in its value as the applied magnetic field and Yb-content increase.