Electrical conductivity of MAl0.97Zn0.03O3−y (M=rare earth)

Electrical conductivity of MAl0.97Zn0.03O3−y (M=La, Sm, Eu, Gd, Dy) and Eu0.9Ca0.1Al0.97Zn0.03O3−y was measured at temperatures from 773 to 1273 K and oxygen partial pressures from 103 to 105 Pa. Effect of ionic radius of M ion in A site on the electrical conductivity of MAl0.97Zn0.03O3−y (M=Rare earth) was discussed. From the oxygen partial pressure dependence of electrical conductivity, MAl0.97Zn0.03O3−y (M=La, Sm, Eu) and Eu0.9Ca0.1Al0.97Zn0.03O3−y were a mixed conductor of oxide ion and hole at temperatures from 773 to 1273 K. Oxide ion conductivity of doubly doped Eu0.9Ca0.1Al0.97Zn0.03O3−y was one order of magnitude large than that of a singly doped EuAl0.97Zn0.03O3−y. Oxide ion conductivity of Eu0.9Ca0.1Al0.97Zn0.03O3−y was compared with those of typical oxide ion conductors and was discussed from the point of view of the tolerance factor for the perovskite structure.