TRANSPORT CRITICAL CURRENT DENSITIES IN Y–Ag–Ba–Cu–O SUPERCONDUCTORS

Abstract

The influence of Ag substitution in amount of 2 mol% instead of Y, Ba and Cu in Y 1 Ba 2 Cu 3 O 7−x high temperature superconductor on magnetic field dependence of the critical current density at 77 K was studied. The samples were prepared by powder technology as well as by citrate method. An increase of transport critical current density as well as its smaller magnetic field dependence was found in case of substitution Ag → Y and Ag → Ba for samples prepared by both methods. In the magnetic field 9 T, the transport critical current density of the sample Y 0.98 Ag 0.02 Ba 2 Cu 3 O 7−x was 0.3 A/cm 2. On the other hand, substitution Ag → Cu lowers transport critical current densities in comparison with undoped samples. The effect of Ag substitution was more pronounced in samples prepared by powder technology.