Powders with superparamagnetic Fe3C particles studied with Mössbauer spectrometry

0354265 - ÚFM 2011 RIV GB eng J - Journal Article
David, Bohumil - Schneeweiss, Oldřich - Dumitrache, F. - Fleaca, C. - Alexandrescu, R. - Morjan, I.
Powders with superparamagnetic Fe3C particles studied with Mössbauer spectrometry.
Journal of Physics: Conference Series. Roč. 217, č. 1 (2010), 012097. ISSN 1742-6588. E-ISSN 1742-6596.
[International Conference on the Applications of the Mossbauer Effect (ICAME 2010). Vídeň, 19.07.2009-24.07.2009]
R&D Projects: GA ČR GA202/08/0178; GA MŠMT 1M0512
Institutional research plan: CEZ:AV0Z20410507
Keywords : Fe3C * superparamagnetism * Mössbauer spectroscopy * magnetic measurements * laser-induced pyrolysis
Subject RIV: BM - Solid Matter Physics ; Magnetism
http://iopscience.iop.org/1742-6596/217/1/012097

Two nanopowders with superparamagnetic Fe3C particles were synthesised by the method of laser-induced pyrolysis of gaseous precursors. Both were characterised by X-ray diffraction, Mössbauer spectrometry and standard magnetic measurements. The mean crystallite size of Fe3C was 3 nm for the first sample and 10 nm for the second sample (Scherrer formula), i.e. it was lower than in our previously studied ferromagnetic Fe 3C-based sample. Fe3C phase in both present samples exhibited by 20 K reduced Curie temperature which is interpreted as a nanosize effect. After annealing of the samples at 1073 K for 30 minutes the Curie temperature of the Fe3C phase in both samples matched its standard bulk value. Beside Fe3C phase also Fe3O4 and carbon black were present in the synthesised samples.
Permanent Link: http://hdl.handle.net/11104/0193306