Phase Structure and Heat Generation in the Co-Precipitated Magnetite Nanoparticles

Abstract

In the present studies the phase structure and magnetic ordering of magnetite nanoparticles were investigated. The powder samples were obtained by co-precipitation from Fe(III) and Fe(II) salts. SiO2 coating was performed using the modified Stöber process. X-ray diffraction studies revealed presence of the only one Fe3O4 crystalline phase both for the non-coated and SiO2-coated samples. The Mössbauer studies have shown differences in shapes of measured spectral lines for Fe3O4 particles subjected to the Stöber process and non-coated particles. The heating efficiency was measured for glycerol dispersed nanoparticles. The analysis have shown changes in specific loss power depending on the concentration of the nanoparticles and amplitude of alternating magnetic field.

Fe3O4 Magnetic Nanoparticles Obtained by the Novel Aerosol-Based Technique for Theranostic Applications

“…Furthermore, the effect of a slightly higher d b than d t for dispersions used for measurements should not be neglected. Much lower SLP values for studied AeroNPs compared to SLP measured for dispersion of bare co-precipitated Fe 3 O 4 nanoparticles [38,39] and these coated with TEA-oleate [9] might be related to the smaller sizes of the 2AeroNPs-top and 2AeroNPs-bottom and their smaller agglomerates formed before coating them with TEA-oleate. The possible factor that might influence the differences in obtained SLP is the impact of TEA-oleate coating on the magnetic properties of the nanoparticles.…”

“…As shown in Figure 10, the TEA-oleate coating caused a significant reduction of the magnetic moment (M) of NPs. Furthermore, SLP measurements reported in [9,38,39] were performed for NPs dispersed in glycerol, which can alter the relaxation mechanism in NPs subjected to high-frequency external magnetic fields. The ILP(f ) dependencies were of the same order of magnitude for both H = 5 kA/m and H = 15 kA/m.…”

“…An efficient and low-cost method used for the synthesis of Fe 3 O 4 NPs is co-precipitation [38,39]. This involves dropwise addition of the basic solution into the solution of salts containing Fe 2+ and Fe 3+ ions.…”

Phase Structure and Heating Efficiency of As-Synthesised Iron-Oxide Nanoparticles and after Long Time Storage in Glycerol

“…The heating efficiencies of the magnetite nanoparticles dispersions in a glycerol and specific loss powers (SLP) were determined for dispersion of nanoparticles produced using both methods as well as for Fe 3 O 4 sample kept in glycerol for 18 months. The details of self-constructed setup for measurements of heating efficiency of nanoparticle dispersions was widely described in [7].…”

“…For this purpose it is rather difficult to compare results obtained in various labs. Therefore, in the present studies two different processing routes that were described in papers [4,7], which led to obtain nanoparticles of various crystallite sizes were used. Furthermore, the phase constitution plays also an important role in the performance of nanoparticle dispersion.…”