This paper describes the effect of oxygen vacancies, which are induced by a carbothermal reduction process and spark plasma sintering (SPS) treatment, on the thermoelectric properties of spinel-structured zinc ferrites Zn x Fe 3 − x O 4 (0.2 ≤ x ≤ 1.0). Characterization of the oxygen-deficient Zn x Fe 3 − x O 4 − ? materials revealed that Zn 2 +preferentially occupy the octahedral B -sites and that valence modification of Fe 3 + to Fe 2 + occurred, resulting in an excess of n-type carriers at B -sites and an increased power factor. In addition, Co substitution enhanced the power factor for the materials over the entire investigated temperature range. Compared with the carbothermal reduction process, SPS treatment effectively introduced oxygen vacancies within a short time and resulted in a material with a substantially improved electrical conductivity.
Research papers (academic journals)
