Magnetoresistance studies of PbO addition in YBa_2Cu_3O_(7-δ) superconductor

摘要

The effect of PbO addition on the superconducting properties of YBa_2Cu_3O_(7-δ)(Y-123) polycrystalline phase has been investigated through samples with x wt.% PbO ( x= 0 -4.5) addition prepared using standard solid state reaction method. Electrical transport measurements indicate that samples with x = 1- 3 have their current density, at self magnetic field, J(0), increased about 50%. Their magnetic field dependent J_c(H) has been measured in liquid nitrogen, and the activation energies have been determined using the TAFF model which shows an enhanced flux pinning proprieties. TEM and EDX analyses have shown that Pb reacts with Y-123 phase to form nanometric Pb-rich phase intergrown in Y-123 superconductors matrix. These inhomogeneities may be the origin of strong pinning.