Ba2Y1Cu3O7-y Oxidation by Thermodynamic Nonequilibrium High-Temperature (TNH) Plasma

Abstract
In order to obtain high-T c superconducting Ba-Y-Cu-O materials, we have studied a method used to supply the oxygen content using a thermodynamic nonequilibrium high-temperature (TNH) plasma. Compared with the usual glow discharge, very-high-density atomic oxygen was observed in the TNH plasma. Treatment of the TNH plasma showed the recovery of quenched samples from the tetragonal structure to an orthorhombic 90-K superconductor within 30 min at 300°C. This is superior to usual oxidation techniques of an atmospheric oxygen anneal and a glow discharge plasma from the viewpoint of short period and low temperature.