Electrical conductivity of BaM ₂ O ₄ (M = Nd, Sm) with a spinel structure

Complex oxides with a spinel structure can be considered as promising electrolyte materials for electrochemical devices to be used in energy generation. In this paper, complex oxides with a spinel structure were obtained, and their electrical conductivity properties at various pH2O and pO2 were investigated for the first time. These compositions are unstable in a humid atmosphere and decompose to barium hydroxide and metal oxide. The electrical conductivity values of BaNd2O4 and BaSm2O4 spinels must be measured strictly in an atmosphere with controlled humidity. The nature of their conductivity is mixed ionic-hole. The conductivity value of the BaNd2O4 composition is higher than that of the BaSm2O4 composition. The greatest values of the ionic conductivity were recorded for the BaSm2O4 composition, in which the share of oxygen ionic transport reaches up to 85% at low temperatures. The values of electrical conductivity at 700 oC are –3.2 and –3.6 S/cm for the BaNd2O4 and BaSm2O4 compositions; the values of ionic conductivity are –3.7 and –4.2 S/cm, correspondingly.