부양가스응축법에 의해 제조된 철산화물 나노 분말의 자기적 특성연구

Abstract

Nanoparticles of iron oxides have been prepared by the levitational gas condensation (LGC) method, and their structural and magnetic properties were studied by XRD, TEM and Mossbauer spectroscopy. Fe clusters were evaporated from a surface of the levitated liquid Fe droplet and then condensed into nanoparticles of iron oxide with particle size of 14 to 30 nm in a chamber filled with mixtures of Ar and O2 gases. It was found that the phase transition from both γ-Fe2O3 and α-Fe to Fe3O4, which was evaluated from the results of Mossbauer spectra, strongly depended on the O2 flow rate. As a result, γ-Fe2O3 was synthesized under the O2 flow rate of 0.1≤Vo2(l/mim)≤0.15 , whereas Fe3O4 was synthesized under the O2 flow rate of 0.15≤Vo2(l/mim)≤0.2.