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Structural and magnetic properties of sol-gel derived CaFe2O4 nanoparticles.
- Source :
-
Journal of Magnetism & Magnetic Materials . Apr2018, Vol. 451, p526-531. 6p. - Publication Year :
- 2018
-
Abstract
- Calcium ferrite nanoparticles with average crystallite size of ∼11 nm have been synthesized by sol-gel method by mixing calcium and ferric nitrates in stoichiometric ratio in the presence of ethylene glycol. As-synthesized nanoparticles were annealed at different temperatures and their structural and magnetic properties have been evaluated. X-ray diffraction studies showed that unlike most ferrites, as-synthesized cubic calcium ferrite showed a slow transformation to orthorhombic structure when annealed above 400 °C. Single phase orthorhombic CaFe 2 O 4 was obtained upon annealing at 1100 °C. Divergence of zero field cooled and field cooled magnetization curves at low temperatures indicated superparamagnetic behavior in cubic calcium ferrite particles. Superparamagnetism persisted in cubic samples annealed up to 500 °C. As-synthesized nanoparticles heat treated at 1100 °C exhibited mixed characteristics of antiferromagnetic and paramagnetic grains with saturation magnetization of 0.4 emu/g whereas nanoparticles calcined at 400 °C exhibited superparamagnetic characteristics with saturation magnetization of 22.92 emu/g. An antiferromagnetic to paramagnetic transition was observed between 170 and 190 K in the sample annealed at 1100 °C, which was further confirmed by Mössbauer studies carried out at different temperatures across the transition. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03048853
- Volume :
- 451
- Database :
- Academic Search Index
- Journal :
- Journal of Magnetism & Magnetic Materials
- Publication Type :
- Academic Journal
- Accession number :
- 128718558
- Full Text :
- https://doi.org/10.1016/j.jmmm.2017.11.102