Study on resistivity anisotropy and flux pinning of Bi2−xPbxSr2CaCu2Oy single crystals

Bi2−xPbxSr2CaCu2Oy ((Bi,Pb)-2212) single crystals with a large doping range up to x=0.8 have been grown by the conventional self-flux method. The resistivity anisotropy of (Bi,Pb)-2212 single crystals and their transport properties under applied magnetic fields with H∥c have been systematically studied. In-plane resistivity (ρab), out-plane resistivity (ρc) and anisotropy (γ) of (Bi,Pb)-2212 are significantly reduced by heavy Pb doping. The dissipation behavior of (Bi,Pb)-2212 single crystals in the mixed state can be well described by the thermally activated flux creep model and flux creep is obviously suppressed for heavily Pb-doped single crystals. The origin of the improved flux pinning is suggested to stem mainly from the reduced anisotropy and the improved coupling strength between Cu–O layers due to Pb-doping.