Effect of Ag2O doping on the superconductivity of the BiPbSrCaCuO oxide

Electromagnetic properties of Ag2O doped and undoped BiPbSrCaCuO superconductor were evaluated to investigate the effect of pinning center on the magnetic shielding and suspension/levitation phenomena. The residual magnetization ΔM=M+−M− increased with dopant concentration, a maximum for 2% doping, wherein a fine uniform dispersion of Ag particles was observed. The magnetic shielding was evaluated by measuring the induced voltage in secondary coil by placing the sample in between primary coil. The voltage initially set to 0.5 V, decreased to 0.17 and 0.28 V, respectively for the undoped and 2% Ag2O doped samples. The much less change in the induced voltage for the 2% doped sample is attributed to the increased flux shielding by shielding vortex current.