Abstract
Alkaline earth cation doped PrGaO3 dense ceramics, Pr1-xMxGa1-yMgyO3-δ (M=Ca, Sr, and Ba), were synthesized by using a solid-state reaction method, and their total conductivity was measured under different kinds of atmospheres. The optimum dopant for the enhancement of conductivity was Sr for the Pr site, and Pr0.9Sr0.1Ga0.85Mg0.15O3-δ (PSGM) showed higher electrical conductivity than other systems. From the total electrical conductivity values measured in Ar and O2, it is strongly suggested that p-type electronic conduction is dominant in all of the doped PrGaO3 system. The difference between the conductivity in O2 and that in Ar was the largest in Pr0.9Ca0.1Ga0.85Mg0.15O3-δ (PCGM) and the smallest in PSGM. To examine whether proton conduction occurs in Pr1-xCaxGa1-yMgyO3-δ system, the total electrical conductivity in Pr0.93Ca0.07Ga0.85Mg0.15O3-δ was measured by changing the partial pressure of O2 and H2O (or D2O) in the atmosphere. The results indicate that Pr0.93Ca0.07Ga0.85Mg0.15O3-δ predominantly shows hole conduction below 873 K, and proton conductivity is negligibly small.
