Effect of cobalt content on the properties of quintuple perovskites Sm2Ba3Fe5-xCoxO15-δ

Quintuple perovskites Sm2Ba3Fe5-xCoxO15-δ (x ​= ​0.5, 1.0 and 1.5) have been prepared by glycerin-nitrate technique in air. The phase purity was confirmed by XRD. Partial substitution of Co for Fe decreases the oxygen content and thus the mean oxidation state of 3d-metals. It also slightly decreases the thermal expansion coefficient of oxides. Positive value of the Seebeck coefficient confirmed p-type conductivity, though the thermopower decreases as the Co content increases. The temperature dependence of electrical conductivity reveals a maximum at 550–750°С. © 2021 Elsevier Inc.Russian Foundation for Basic Research, РФФИ: 18-33-00822; Ministry of Education and Science of the Russian Federation, Minobrnauka: 075-15-2019-1924The work was financially supported in parts from the Ministry of Science and Higher Education of Russian Federation [Agreement No. 075-15-2019-1924 ] and Russian Foundation for Basic Research [project No 18-33-00822 ]