Field and temperature dependence of the c-axis critical current in Bi2Sr2CaCu2O8+ delta single crystals at the melting and two-dimensional decomposition fields.

Abstract

Measurements of the V-I characteristics and critical currents along the c axis are reported for a number of small single crystals of ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8+\mathrm{\ensuremath{\delta}}}$ as a function of temperature, magnetic field, and oxygen stoichiometry. The primary aim of this investigation was to investigate changes in the c-axis resistivity resulting from misalignment of pancake vortices across superconducting ${\mathrm{CuO}}_{2}$ planes at the melting and 3D-2D decomposition fields. Although the field dependence of the critical current is shown to scale with the field at which the 3D-2D decomposition takes place, no significant change in the field dependence was observed at either phase transition. This implies a short-range correlation of the positions of pancake vortices across planes persisting well above such transitions.