Magnetic properties of γ-Fe2O3 nanopowder synthesized by atmospheric microwave torch discharge

Abstract

A nanopowder containing -Fe2O3 particles was synthesized by adding a gas mixture of H2/Fe(CO)5 into a microwave torch discharge at 1 bar. The presence of γ-Fe2O3 phase was confirmed by powder X-ray diffraction (mean crystallite size dXRD = 24 nm). The dominating characteristic sextets of γ-Fe2O3 were identified in the Mössbauer spectrum taken at 5 K. The presence of pure Fe 2O3 in the nanopowder was excluded. The Mössbauer spectrum taken at 5 K exhibited six times larger total spectrum area than the Mössbauer spectrum taken at 293 K. Zero field cooled/field cooled curves measured down to 4 K in the magnetic field of 7.9 kA/m are reported.