The O uptake and removal from Cu3Ba2(PrxY1-x)O7 ceramics, at temperatures ranging from 300 to 1000K, was monitored by means of  in situ  resistivity measurements. The out-diffusion of O was studied by annealing oxygenated samples in ambient air at a constant heating rate. It was found that, regardless of the value of x, the O concentration was preserved at temperatures of up to 600K while O diffused out of the oxide at temperatures higher than 600K. On the other hand, the rate of O removal from Cu3Ba2PrO7 was greatly reduced, as compared with the rate for pure Cu3Ba2YO7, and decreased with increasing x-value. Studies of the in-diffusion of O were performed by annealing de-oxygenated samples in ambient air at a constant heating rate. It was found that, regardless of the value of x, O uptake took place at temperatures ranging from 550 to 750K; where the in-diffusion rate depended slightly upon the Pr concentration. The observed resistivity changes of all of the samples, during O interchange with the gas phase, indicated that the number of majority carriers in the oxides was controlled mainly by the O, and seemed to be independent of the Pr concentration; at least for x-values of less than 0.5.

J.E.Diosa, R.A.Vargas, B.E.Mellander: Journal of Physics - Condensed Matter, 1997, 9[22], 4621-6