JOSEPHSON JUNCTION DEVICE FORMED OF OXIDE SUPERCONDUCTOR MATERIAL AND PROCESS FOR PREPARING THE SAME

摘要

A Josephson junction device comprises a single crystalline substrate including a principal surface, an oxide layer formed on the principal surface of the substrate having a step on its surface and an oxide superconductor thin film formed on the surface of the oxide layer. The oxide superconductor thin film includes a first and a second portions respectively positioned above and below the step of the oxide layer, which are constituted of single crystals of the oxide superconductor, and a grain boundary on the step of the oxide layer, which constitutes a weak link of the Josephson junction.