Revisiting the Role of Vacancies in Manganese Related Perovskites

Oxygen engineering is an important tool for on-demand tailoring of manganese related perovskites into optimized performances. Anionic vacancies can be induced in both doped and undoped manganites by means of topotactic reduction processes under oxygen controlled atmosphere. This has given rise to the stabilization of new phases as a consequence of ordering of oxygen vacancies in which Mn2+ appears due to the reducing process. Different reduction pathways are proposed for LaMnO3 and doped systems. FM interactions remain at the octahedral layers when vacancies are longrange ordered. The peculiar magnetic behaviour of new layered perovskite superstructures is discussed.