GROWTH AND CHARACTERIZATION OF PRBA2CU3O7-DELTA SINGLE-CRYSTALS

We report on the growth of PrBa2Cu3O7-delta single crystals in the Al2 O3 and ZrO2 crucibles by flux method. The high influence of the reacti on between crucible and Liquid on the initial melt composition has bee n established. We found that the precipitation of the chemically stabl e compound BaZrO3 and BaAl2O4 occurs by direct chemical reaction betwe en BaCuO2 and ZrO2 or Al2O3 crucibles materials. Free separated crysta ls with maximum size of 3 x 5 x 0.1 mm(3) have been obtained. PrBa2Cu3 O7-delta crystals exhibit a typically semiconducting behaviour. The re sistivity depends on the thermal treatment and decreases by about two orders of magnitude for oxygen concentration between 6.65 to 6.95.