Percolation and the Josephson effect in high-Tc superconducting composites based on yttrium ceramics

Abstract

Percolation processes and the magnetic susceptibility are investigated in composites based on yttrium high-Tc superconductors (Y-HTSCs). The superconducting fraction in the composites is determined for different amounts of an added nonsuperconducting fraction. The limit of percolation conduction via superconducting grains for a HTSC–insulator composite is (17±2)% superconducting fraction by volume. The Josephson properties of composite superconductors near the percolation limit are investigated.