Enhanced magnetic properties in low doped La1-xBaxMnO3+δ (x=0, 0.1 and 0.2) nanoparticles

Low doped colossal magnetoresistance La1−xBaxMnO3+δ nanoparticles are synthesized by a sol–gel method along with the parent compound LaMnO3+δ. The Reitveld refinements on the XRD patterns show that they are crystallized in structure other than their stoichiometric bulk. The crystal structure indicates excess oxygen/cationic vacancies in the compound. The magnetic measurements reveal that the ferromagnetic Curie temperature (TC) is enhanced after oxygen annealing. The observed TC is higher than that of their stoichiometric bulk compounds and the values are comparable to the reported tensile strained epitaxial thin films. The estimated Mn4+/Mn3+ ratio is found to increase in the nanocrystalline samples compared to their bulk samples annealed under the same oxygen atmosphere. The enhancement in Curie temperature could be correlated with the excess oxygen/cationic vacancies. - Highlights: • Barium doped LaMnO3 nanoparticles are synthesized in low doped region by the sol–gel method. • Their crystal structure indicates the existence of oxygen excess/cationic vacancies. • Oxygen annealing enhances the Curie temperature higher than their bulk value. • Enhanced magnetic properties could be correlated with the excess oxygen