ELECTRICAL-CONDUCTIVITY AND DEFECT STRUCTURE OF LANTHANUM-DOPED (U,PU)O-2+/-X

The electrical conductivities sigma of La-z(U0.8Pu0.2)(1-z)O-2+/-x (z=0.01 and 0.1) were measured in the range 10(-15) Pa less than or equal to P(O2)less than or equal to 10(-1.5) Pa at 1273 K. Three different dependences of sigma on P-O2 for La-z(U0.8Pu0.2)(1-z)O-2+/-x (z=0.01 and 0.1) were observed, similar to the results for the sample not containing lanthanum (z=0). An additional dependence of sigma on P-O2 was observed for the sample with z=0.1, similar to that of the hypostoichiometric La0.1U0.9O2-x, phase, suggesting the existence of the hypostoichiometric La-0.1(U0.8Pu0.2)(0.9)O-2-x phase. The effect of doping on the defect structure and the electrical conduction mechanism of La-z(U0.8Pu0.2)(1-z)O-2+/-x (Z = 0.01 and 0.1) is discussed.