Makovec, Darko and Kodre, Alojz and Arčon, Iztok and Drofenik, Miha (2009) Structure of manganese zinc ferrite spinel nanoparticles prepared with co-precipitation in reversed microemulsions. Journal of Nanoparticle Research, 11 (5). pp. 1145-1158.
Official URL: http://www.springerlink.com/content/v42148j13r763r...
The structure of Mn0.5Zn0.5Fe2O4 spinel ferrite nanoparticles is studied as a function of their size and the experimental conditions of their synthesis using X-ray absorption spectroscopy. The nanoparticles of different sizes down to approximately 2Â nm and with a narrow size distribution were synthesized using co-precipitation in reverse microemulsions. Simultaneous refinement of the X-ray absorption fine structure (EXAFS) of three constituting metals shows a migration of Mn and Zn ions to the octahedral site of the spinel lattice compensated by the corresponding migration of the Fe ions. To a smaller extent, Mn ions switch the occupation site already in bulk and in larger nanoparticles, while a sporadic migration of Zn is detected only in the nanoparticles with sizes below approximately 5Â nm. X-ray absorption near edge structure (XANES) reveals considerable variations in the position of the Mn K edge, suggesting the average Mn valence in the nanoparticles to be higher than 3+. Annealing at 500Â Â°C relaxes the structure of as-synthesized nanoparticles toward the structure of the ceramic bulk standard.
|Subjects:||Physical Science > Nanomagnetics|
Material Science > Nanostructured materials
|Deposited On:||29 Jun 2009 15:19|
|Last Modified:||29 Jun 2009 15:19|
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