Magnetic Enhancement of γ-Fe₂O₃ Nanoparticles by Sonochemical Coating

Abstract

We show that sonochemistry is an efficient and facile route for quantitative coating of γ-Fe2O3 nanoparticles with octadecyltrihydrosilane (OTHS, CH3(CH2)17SiH3). The presence of C−H stretching (2950−2850 cm-1) and bending (1475−1375 cm-1) bands, and the absence of peaks at 2150 and 925 cm-1 (Si−H stretching and bending respectively) confirm the presence of grafted hydrocarbon chains in the irradiated sample, hence the reaction of OTHS with γ-Fe2O3 nanoparticles. The coated nanoparticles show increased magnetization compared to the uncoated ones. X-ray diffraction, magnetization studies, Mössbauer spectra, and electron paramagnetic resonance spectra reveal that the magnetic ordering is more prominent in the OTHS-coated γ-Fe2O3 sample because of improved crystallinity.

Applications of Ultrasound to the Synthesis of Nanostructured Materials

“…Ulman and coworkers have also reported sonochemical coating of silane over TiO 2 and g-Fe 2 O 3 nanoparticles. [109,110] Very recently, Chen and coworkers synthesized silica coating over indium tin oxide (ITO) nanoparticles via a sonochemical route. [111] Sonochemical deposition of metal sulfides over metal oxides provides an alternative way to produce hetero-structured core/shell composites.…”

One-step synthesis of maghemite (γ-Fe2O3) nano-particles by wet chemical method

“…Nano-particles have become the focus of modern materials science because of their potential technological importance, which stems from their unique physical properties [1]. Their electronic, magnetic and optical properties contribute attractive prospects in the design of new electronic and optical device, information storage, color imaging, bio-separation, magnetic refrigeration, ferro fluids, gas sensors, etc.…”

Zero-field and in-field Mössbauer spectroscopy as a tool for structural and magnetic characterization of maghemite (γ-Fe2O3) nanoparticles

“…They include laser pyrolysis [18], coprecipitation method [19], electrochemical method [20], sol-gel method [21,22], aerosol technique [23], microemulsion method with ionic surfactants [24], physical methods such as ball-milling [25] and film deposition [26], separation of particles by means of magnetic chromatography [27], sonochemistry [28], spray pyrolysis [29] or microwave plasma method [30]. These preparation methods are used for different research goals since some of them are, for example, well suited for the formation of uniformly sized particles with negligible size distribution while other ones give rise to the particles with desired enhanced magnetic properties.…”