Measurement of current voltage characteristics of single grain boundaries in melt textured bulk YBa2Cu3Ox

Abstract
We have investigated the electrical properties of small parts of single grain boundaries in melt textured YBa2Cu3Ox. Similar measurements on grain boundary networks were also made to obtain composite properties. The results of Tc measurements and current‐voltage characteristics in zero and small magnetic fields are presented. The R(T) characteristics suggest that there is second phase segregation in some parts of the grain boundary area. The current‐voltage characteristics showed three different types of behavior: Resistive, Josephson‐like, and flux flow. The Ic(B) data of Josephson junctions suggest that nonsuperconducting inclusions divide the grain boundaries into smaller single junctions.