Resumo

HERNANDEZ, E.; SAGREDO, V.  e  DELGADO, G.E.. Synthesis and magnetic characterization of LaMnO₃ nanoparticles. Rev. mex. fis. [online]. 2015, vol.61, n.3, pp.166-169. ISSN 0035-001X.

LaMnO₃ Nanoparticles systems were prepared by the sol-gel auto-combustion method, in order to analyze the structure and magnetic behavior presented by the compound prepared following a new alternative route of synthesis. Structural characterization, morphology and crystallite size was performed by X-ray diffraction (XRD), infrared spectroscopy (IR) and electron microscopy (TEM). The XRD study together with a Rietveld analysis showed that the LaMnO₃ compound crystallized in a perovskite hexagonal structure. The IR spectra showed that the compound has tensile energy bands in the Mn-O-Mn bonds related with the octahedron MnO₆; which are attributed to a characteristic vibration of the ABO₃ perovskite. An estimated size and morphological analysis was carried out by applying the Scherrer's formula and using Transmission Electron Microscopy (TEM), revealing non-spherical shape and particle sizes between 13 nm and 18 nm. The magnetic measurements M(T) were performed by using zero-field-cooled (ZFC) and field-cooled (FC) protocols which revealed a positive Weiss temperature indicating the presence of ferromagnetic interactions with a Curie temperature, T_C = 150 K.

Palavras-chave : Auto-combustion; curie temperature; magnetization; manganites; nanoparticles; ferromagnetism; perovskite; Sol-Gel.

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