Disparity in electrical and magnetic properties of isostructural oxygen-deficient perovskites BaSrCo2O6-delta and BaSrCoFeO6-delta

作者：Hona Ram Krishna; Ramezanipour Farshid^*

来源：Journal of Materials Science: Materials in Electronics , 2018, 29(16): 13464-13473.

DOI：10.1007/s10854-018-9471-8

Despite having the same crystal structure, the two oxygen-deficient perovskites, BaSrCo2O6-delta and BaSrCoFeO6-delta have significantly different electrical conductivity and magnetic properties, highlighting the important effect of oxygen stoichiometry. These two materials have been investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, variable-temperature electrical conductivity and magnetization studies. BaSrCo2O6-delta shows magnetic properties consistent with antiferromagnetic order, whereas BaSrCoFeO6-delta exhibits the presence of uncompensated moments and short-range ferrimagnetism. XPS and iodometric titrations show a greater degree of oxygen vacancies in BaSrCo2O6-delta compared to BaSrCoFeO6-delta. Cobalt is in di- and trivalent states in both compounds and iron is in tri- and tetravalent states in BaSrCoFeO6-delta. The differences in electrical conductivity are remarkable, where BaSrCo2O6-delta shows nearly temperature-independent conductivity up to 400 A degrees C, above which a semiconducting behavior sets in and persists up to 900 A degrees C. However, BaSrCoFeO6-delta exhibits semiconductivity up to 200 A degrees C, followed by a downturn in conductivity from 200 to 900 A degrees C, similar to the behavior observed in metallic systems.

• 出版日期2018-8