Magnetoresistance studies of Tl-1223 phase substituted by scandium

Abstract

Superconducting samples of type TlBa2Ca2-xScxCu3O9-δ with x = 0.0, 0.025, 0.05, 0.1, and 0.2 have been prepared via solid-state reaction technique. The effect of weak magnetic fields up to 4.4 kG on the electrical resistivity of the prepared samples has been studied to investigate the flux motion for this phase. The results reveal a slight shift in the superconducting transition temperature Tc and an increase in the superconducting transition width ΔT with increasing magnetic fields. The experimental data fit well with the thermally activated flux creep model and the activation energy U(B) shows a power law dependence on magnetic field as B. Also, the transition width is related to the magnetic field according to the relation ΔT α Bn. The values of β and n are strongly dependent on the Scandium-content. The temperature and magnetic field dependence of the activation energy U(B, T) is found to be U(B, T) ~ ΔT B-η, where η = β + n. The critical current density Jc(0) and the upper critical field Bc2(0) are calculated, from the above measurements, as a function of Scandium-content. Finally the electronic thermal conductivity κe, estimated from Wiedemann-Franz law, is reported at different applied magnetic fields for the prepared samples.