Magnetic properties and thermal stability of γ′-Fe4N nanoparticles prepared by a combined method of reduction and nitriding

Single-phase gamma-Fe4N nanoparticles have been prepared by a combined method of reduction and nitriding using Fe3O4 nanoparticles as precursor. Their magnetic properties and thermal stability have been investigated systematically. The Fe3O4 precursor synthesized by chemical coprecipitation technique was transformed completely to gamma-Fe4N in an H + NH3 mixed gases at temperature above 500degreesC. A maximum value of saturation magnetization (182 emu/g) was obtained in the gamma'-Fe4N nanoparticles after treating at 700degreesC. The magnetic spectra Of gamma-Fe4N exhibits a pronounced relaxation. (C) 2004 Elsevier B.V. All rights reserved.