Local structure and magnetic properties of Mn3+–O–Fe3+ superexchange interaction in an oxygen-vacant perovskite: Experimental and theoretical study

In this work we report an experimental and theoretical study on the local structure and magnetic properties of Mn3+–O–Fe3+ superexchange interaction for an oxygen-vacant perovskite PrBaMnFeO5+ δ with δ ∼ 0.5. Structural studies were performed by high resolution X-Ray diffraction technique in normal and anomalous scattering, modeled using an orthorhombic biphasic system corresponding to an oxygen-rich and oxygen-poor stoichiometries. Mössbauer spectroscopy showed the presence of two orthorhombic iron sites, one ascribed to a fully octahedral coordination and another, highly distorted, ascribed to a pyramidal coordination, in full agreement with theoretical DFT + U + SO calculations. The samples showed a spin-glass transition at ∼20 K and mainly the presence of Mn3+–O–Fe3+ type-G antiferromagnetic superexchange interactions. However, our theoretical calculations using first principles also suggested that the presence of oxygen vacancies in certain conditions could be possibly promoting local ferromagnetic interactions. Fil: Romero, Mariano. Universidad de la República; Uruguay Fil: Faccio, Ricardo. Universidad de la República; Uruguay Fil: Pardo, Helena. Universidad de la República; Uruguay Fil: Montenegro, Benjamín. Universidad de la República; Uruguay Fil: Richard, Diego. Instituto de Física la Plata (conicet- Universidad Nacional de la Plata); Argentina Fil: Martínez, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional del Noroeste de la Provincia de Buenos Aires; Argentina Fil: Mudarra Navarro, Azucena Marisol. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina Fil: Mombrú, Alvaro W.. Universidad de la República; Uruguay