Effect of metal oxide doping on the superconductivity of YBaCuO ceramics

Electromagnetic properties of CeO₂ doped and undoped YBaCuO superconductors were evaluated to investigate the effect of pinning center on the magnetization and magnetic shielding. The variation DeltaM with doping was maximum for 3% doping and decrease with further doping. The magnetic shielding was evaluated by measuring the induced voltage in secondary coil and the voltage initially set to 0.5 V, decreased to 0.17 V and 0.28 V respectively for the undoped and 3% CeO₂ doped sample. The much less change in the induced voltage for the 3% doped sample is attributed to the increased flux shielding by shielding vortex current. The CeO₂ was converted to fine BaCeO₃ particles which were trapped in YBaCuO superconductor during the reaction sintering. The trapped fine particles, BaCeO₃ may be acted as a flux pinning center.