Influence of annealing on magnesioferrite nanoparticles synthesized by a sol-gel/combustion method

• Autor(a) principal: Biasi, Ronaldo Sergio de
• Data de Publicação: 2009
• Outros Autores: Cardoso, Lúcia Helena Guimarães, Campos, José Brant de, Sanchez Candela, Dalber Ruben, Cunha, Joao Batista Marimon da
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/20793
• topic: Ciência dos materiais; Nanopartículas; Espectroscopia mossbauer; Ressonancia ferromagnetica; Nanoparticles; Mössbauer spectroscopy; Maegnesioferrite

Nanocrystalline particles of magnesioferrite (MgFe2O4) were prepared by a sol-gel/combustion method using iron nitrate, Fe(NO3)3.9H2O, magnesium nitrate, Mg(NO3)2.6H2O, and citric acid, C6H8O7.H2O, and annealed for 2 hours at 400, 500 and 600 °C. The average particle size, determined by X ray diffraction, was found to depend on the annealing temperature and varied from 〈D〉 = 8.1 to 〈D〉 = 17.8 nm. By measuring at several temperatures the relative intensity of the Mössbauer spectra due to superparamagnetic particles and to ferrimagnetic particles, we determined the size distribution of the nanoparticles in the samples. It was found to be a log-normal distribution with a most probable diameter that varied from Dm = 6.4 to 17.2 nm and a full width at half-height ΔD in the 5-6 nm range.