Low-temperature magnetic properties of nanometric Fe-based particles

Abstract

Fe-based nanoparticles were prepared by laser-driven pyrolysis. The assynthesised powder consists of α-Fe and Fe3O 4/γ-Fe2O3 nanoparticles embedded in a pyrolytic carbon matrix. The crystallite size of 1.8 nm for α-Fe was calculated using the Scherrer formula. The as-synthesised nanopowder was superparamagnetic. The maximum of the zero-field cooling curve was observed at 32 K and the distribution of blocking temperatures g{TB) peaked at 11 K. As a result of small particle sizes and the soft matrix, the Lamb-Mössbauer factor f was significantly higher at 4 K than at 293 K.