Effect of lanthanide on the microstructure and structure of LnMn{sub 0.5}Fe{sub 0.5}O{sub 3} nanoparticles with Ln=La, Pr, Nd, Sm and Gd prepared by the polymer precursor method

• Published in: Journal of solid state chemistry 2015-01, Vol.221
• Main Authors: Romero, Mariano, Centro Interdisciplinario de Nanotecnología, Química y Física de Materiales—UdelaR, Montevideo, Faccio, Ricardo, Martínez, Javier, Instituto de Física de La Plata, CCT-La Plata—CONICET, La Plata, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Corrientes, Pardo, Helena, Montenegro, Benjamín, Plá Cid, Cristiani Campos, Pasa, André A.
• Format: Article
• Language: English
• Subjects: CALCINATION; CHELATES; CITRATES; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LAMELLAE; MICROSTRUCTURE; NANOPARTICLES; NANOSCIENCE AND NANOTECHNOLOGY; ORTHORHOMBIC LATTICES; OXYGEN; PEROVSKITE; POLYMERIZATION; POLYMERS; PRECURSOR; SAMARIUM; SMALL ANGLE SCATTERING; SPECTROSCOPY; SYNTHESIS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/J.JSSC.2014.10.028

The synthesis of LnMn{sub 0.5}Fe{sub 0.5}O{sub 3} perovskite nanoparticles by the polymer precursor method showed a strong intrinsic dependence with different lanthanides (Ln=La, Pr, Nd, Sm and Gd). The polymerization level reached in the polymer precursor was proportional to the atomic number of lanthanide with exception of samarium, which showed the formation of a different precursor based in a citrate chelate with ethyleneglycol bonded as adduct. The increasing level of polymerization of the polymer precursors showed the formation of large-size perovskite nanoparticles after its calcination. SAXS and TEM analyses suggested that nanoparticles obtained, using this method, have a squared-like microstructure in connection with the polymer precursor microstructure. Structural analysis showed an orthorhombic structure with a slight decline in the Jahn–Teller distortion when the atomic number of lanthanide increases. Mössbauer spectroscopy showed the presence of a majority site in agreement with the Pbnm orthorhombic structure best fitted with Rietveld refinements and in some cases, a more distorted site attributed to local inhomogeneities and oxygen vacancies. - Highlights: • Precursor polymerization level is lower in the presence of lighter lanthanides. • Lighter lanthanide perovskite nanoparticles after calcination are lower-sized. • Nanoparticles obtained by this method have lamellae microstructure. • Jahn–Teller distortion declines for heavier lanthanide perovskites. • Oxygen vacancy phase was observed in lighter lanthanide perovskites.