CO-CATION CONDUCTIVITY OF SOLID-SOLUTIONS WITH THE GAMMA-KFEO2, STRUCTURE AS A FUNCTION OF AN EXCESS OF ALKALI-METAL OXIDES

The co-cation conductivity of solid solutions with the gamma-KFeO2 str ucture is studied in the systems 1.5M(2)O(3).yTiO(2).2(A(1-x)A(x)')(2) O (M = Ga, Fe; A, A' = K, Rb, Cs; y = 0.75, 0.82). In all cases, the e lectroconductivity is minimal and the activation energy for conduction is maximal at x approximate to 0.8 (polyalkaline effect). The depende nces of the polyalkaline effect on x as well as on the volume of an el ementary cell of the solid solutions are qualitatively similar. Howeve r, these dependences are more pronounced than those pertaining to the systems with the constant ratio M2O3/(Al2O + A(2)'O) = 1 that were stu died previously. The distinction is explained by the difference in the crystal structures.