Anisotropic electric resistivity of superconducting La2-xBaxCuO4-delta single crystals

We report detailed experimental results on the anisotropic electric resistivity rho(T, x) for a series of La2-xBaxCuO4-delta single crystals (x = 0.06, 0.08, 0.09) grown by the TSFZ method. In all as-grown crystals, a semiconducting electric conduction was observed in the normal state both in the ab plane and along the c-axis. After annealing in oxygen, rho(ab)(T) became metallic and rho(c)(T) remained semiconducting above the superconducting transition temperature. Though the change in T-c was small after the annealing, the normal-state resistivity changed significantly. A possible reason for such behaviors was discussed. The resonating valence bond (RVB) model and power law were adopted to fit the experimental data.