Structural and magneto-electrical characterization of cathodes based on rare-earth manganites for solid oxide fuel cells

The subject of the thesis is highly spin-polarized rare earth element-based manganese perovskite structures. Lanthanum-strontium-manganese-oxide (LSMO) ceramics possess unique magnetic and electrical properties which have received lots of attention from researchers and producers of new materials. In addition to the effects of colossal magnetoresistance, magnetic refrigeration, magnetic memory, and magnetic hyperthermia applied in various fields of modern technology, they also possess parameters that make it possible to consider them as frequently used cathode materials for solid oxide fuel cells. In this dissertation, two series of manganite ceramics both produced by B-site substitution are explored. In the first series, 10 % of Mn ions are replaced with various transition metals as Cu, Co, Fe, and Ti in the La0.8Sr0.2MnO3 system and examined the structural, magnetic, and electrical-transport features. In the second series, the influence of iron content on the structural, microstructural, magnetic, and electrical-transport features of the ceramic perovskite manganites of the La0.8Sr0.2Mn1-xFexO3 (x=0.0, 0.05, 0.1, and 0.2) system was investigated. A detailed analysis of the conduction mechanism behind the metal-insulator transition is also discussed. Analyzing structural and magneto-electrical features in these systems and obtaining enhancing physical properties bu B-site substitution offers a possibility to use them in technology.