Abstract
Effect of oxygen partial pressure on the phase equiliria of YBa2 Cu3 Oy at high temperature was investigated solely by electrical conductivity measurements and X-ray diffraction. Arrhenius plots of the electrical conductivities of YBa2 Cu3 Oy measured under various oxygen pressures consisted of five straight lines, whose slopes were almost the same independent of Po2. The temperatures at which the straight lines intersected corresponded to the phase transition temperatures determined by X-ray diffraction analyses and agreed with those reported by other researchers. These results suggested that the electrical conductivity measurement might be very usefull to to detect the phase transition temperatures of this material at high temperature.
