Sonochemical Preparation and Size-Dependent Properties of Nanostructured CoFe₂O₄ Particles

Abstract

Nanostructured CoFe 2 O 4 particles were prepared by a sonochemical approach, first by preparation of the amorphous precursor powders, followed by heat treatment at relatively very low temperatures. The precursor was prepared by sonochemical decomposition of solutions of volatile organic precursors, Fe(CO) 5 and Co(NO)(CO) 3 , in Decalin at 273 K, under an oxygen pressure of 100-150 kPa. The amorphous nature of these particles was confirmed by various techniques, such as scanning and transmission electron microscopy (SEM and TEM), electron microdiffraction, and X-ray diffractograms. Magnetic measurements, Mo ¨ssbauer, and electron paramagnetic resonance (EPR) spectral studies indicated that the as-prepared amorphous particles were superparamagnetic. The Mo ¨ssbauer parameters and the significantly low (45 emu/g) observed saturation of magnetization of the annealed sample, compared to that of the bulk sample (72 emu/g), reflected its nanocrystalline nature.

High Efficacy in Hyperthermia-associated with Polyphosphate Magnetic Nanoparticles for Oral Cancer Treatment

“…This value is smaller than the values reported for bulk maghemite at 300 K (MS=76 emu/g) [31] but is similar to the MS values previously reported for maghemite nanoparticles in the range size of 5-10 nm [32]. The difference in the saturation magnetization between the bulk and the nanosized material can be attributed to the small particle size effect [33].…”

Synthesis, Characterization, and Toxicity Evaluation of Dextran-Coated Iron Oxide Nanoparticles

“…Magnetization curves (M-H loop) for the DIO-NPs measured at room temperature are presented in Figure 4. According to previous studies [44,45] the DIO-NPs, shows negligible value of coercivity which indicates the presence of superparamagnetic phase. From hysteresis measurements, the remnant magnetization (Mr) and coercivity fields (Hc) were equal to 0 Oe at 300 K. On the other hand, the calculated magnetization value of DIO-NPs was found to be 9.84 emu/g.…”

Fabrication and magnetic properties of hierarchical nickel microwires with nanothorns

“…Therefore, a relatively lower H c value was shown. As for the decreased value of M s , it might be due to the decrease in the particle size accompanied by an increase in the surface area, and the magnetic interaction between the subunits, which reduced the total magnetic moment at a given field [28][29][30].…”