Dissipation processes in transport-current-carrying and Bi_2Sr_2Ca_2Cu_3O_(10+δ) and Bi_2Sr_2Cu_2O_(8+δ) thin films

摘要

The interlayer Josephson coupling in highly anisotropic Bi-based superconducting cuprates manifests itself in the existence of a finite critical-current density in zero applied magnetic field. By analysing the shape of the current-voltage characteristics in terms of quasi-two-dimensional vortex unbinding, it was found that the interlayer coupling vanishes above the hypothetical Kosterlitz-Thouless transition temperature, in agreement with Monte Carlo simulations. The nonvanishing coupling between the superconducting layers makes possible the occurrence of a vortex-glass state even in the case of an accentuated anisotropy. Bose-glass scaling of the E(J) curves were obtained for both Bi_2Sr_2Ca_2Cu_3O_(10+δ) and Bi_2Sr_2CaCu_2O_(8+δ) films containing columnar defects oriented along the c axis. The scaling revealed wide critical regions and large values of the dynamic critical exponent.