SOME CHARACTERISTICS OF GRANULAR SUPERCONDUCTIVITY IN GDBA2CU3O7-Y CERAMICS

The behavior of granular superconductivity of single‐phase GdBa 2 Cu 3 O 7-y ceramics has been studied systematically by measuring the crystal structure, superconductivity, magnetoresistance, I‐V characteristics, etc. The grain‐boundary Josephson effect, the behavior of the current‐carrying resistive state, and the percolation nature, etc., have been observed. Based on the three‐dimensional network model of Josephson junctions, the phenomena noted above are explained satisfactorily