Levitation-jet synthesis of In-O nanoparticles with room-temperature ferromagnetic properties

Abstract

Octahedral and roughly spherical In-In2O3 nanoparticles ranging in average particle size from 30 up to 300nm were prepared by levitation-jet aerosol synthesis through condensation of metal indium vapor in helium gas flow with gaseous oxygen/air injection at ambient and reduced pressure. Scanning electron microscopy (SEM), X-ray diffraction (XRD), BET measurements, UV–vis, FT-IR, Raman, XPS, and vibrating-sample magnetometry (VSM) characterized the nanoparticles. Room-temperature ferromagnetism with maximum magnetization of up to 0.17emu/g was recorded for the nanoparticles. The results indicate a predominant role of the actual microstructure on the nanoparticle properties. It is suggested that the observed ferromagnetic ordering may be related to intrinsic defects at the In/In2O3 interface structure of such a composite material. This suggestion is in good agreement with the results of optical and XPS experiments on the NPs.