Effect of Oxygen Nonstoichiometry on Electrical Conductivity and Thermopower of Gd0.2Sr0.8FeO3 Ferrite Samples

Abstract

The behavior of electrical resistance and thermopower of the Gd 0.2Sr0.8FeO3-δ ferrite samples with the perovskite structure and their stability in the inert gas atmosphere in the temperature range of 300–800 K have been investigated. It has been established that, in the temperature range of interest, the thermoelectric properties in the heating‒cooling mode stabilize at δ ≥ 0.21. Temperature dependences of the electrical resistance obtained at different δ values have been shown to obey the activation law up to the temperatures of active removal of oxygen from the sample. As the temperature increases, the semiconductor‒semiconductor electronic transitions with the activation energy lowering have been observed. The maximum thermoelectric power factor of 0.1 µW/(cm • K2) has been obtained at Т = 800 K.