Long and Short Ordering in Cationic Deficient Manganese Related Brownmillerites

Abstract

Ever since colossal magnetoresistance (CMR) was discovered in Ln1-xAExMnO3 (Ln=lantanide; AE alkaline-earth), establishing the relationship between structure and properties constitutes a prominent place in the landscape of solid-state science because of its intriguing potential applications. The occurrence of different Mn3+/Mn4+ ratios seems to be responsible of the different magnetic behaviours observed and can be tuned by either changing i) the Ln/AE ratio or ii) the oxygen content, i.e., Ln1-xAExMnO3-δ. Although plenty of works has been devoted to the first point, less effort has been devoted to study the effect of the compositional variations at the oxygen sublattice. In spite of the partial break-up occurring at the 3D network of octahedral sharing corners, responsible of the double exchange interactions the oxygen deficient compounds exhibits complex magnetic and electric properties.