Comparison of the fluctuation influence on the resistive properties of the mixed state of Bi2Sr2CaCu2 O8+x and of thin films of conventional superconductor

Abstract

The resistive properties of layered HTSC Bi2Sr2CaCu2O8+x in the mixed state are compared with those of thin films of conventional superconductors with weak disorder (amorphous Nb1-xOx films) and with strong disorder (Nb1-xOx films with small grain structure). The excess conductivity is considered as a function of the superconducting electron density and the phase coherence length. It is shown that the transition into the Abrikosov state differs from the ideal case in both Bi2Sr2CaCu2O8+x and Nb1-xOx films, i.e. the appearance of the long-range phase coherence is a smooth transition in both cases. The quantitative difference between thin films with weak and strong disorder is greater than the difference between layered HTSCs and conventional superconductors, showing that the dimensionality of the system, rather than the critical temperature, is the key factor ruling fluctuation effects.