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摘要
Two samples of nanopowders containing superparamagnetic Fe3C and Fe3O4/gamma-Fe2O3 particles and carbon black were synthesized by the method of laser-induced homogeneous pyrolysis of gaseous precursors. Both were characterized by XRD, HR-TEM, Mossbauer 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. Fe3C phase in both samples exhibited reduced Curie temperature and smeared ferromagnetic-paramagnetic transition. After annealing of the samples at 800 degrees C for 30 min the Curie temperature of the recrystallized Fe3C phase in both samples was similar to 214 degrees C (standard bulk value).
- 出版日期2010-7
