Gamma-radiation and gas environment impact on percolation processes in Yttrium High Temperature Superconductor Ceramics (Y HTSC)

Outcomes of investigation of gamma-radiation impact on processes of electro transmission in Y HTSC under the air and hydrogen environment conditions were presented. Variations of the critical parameters of superconducting transition (Tc, Jc) and the strength of superconducting phase were controlled at irradiated samples. The samples were also used to analyze the gamma-radiolysis product composition. The observed effects show fluctuations of the percolation current flow parameters (L- length of percolation path, S- cross-section) and enhancement of 'weak' coupling at the intergranular boundaries under small gamma-radiation doses. However, the mechanism of percolation decreasing is suppressed by degradation of the superconducting matrix when D>4 MGy