Zinc-ferrite, nickel-ferrite and mixed nickel-zinc ferrites were successfully synthesized via the thermal decomposition method from acetylacetonate complexes. To control the particle size and enhance dispersibility in an aqueous medium, starch, a natural and biocompatible compound, was used for the first time for coating such magnetic powders. X-ray powder diffraction (XRPD) was performed to study the structural properties of all samples. The presence of a single-phase spinel structure as well as the cation distribution in both sites of all investigated magnetic powders was confirmed. The values of unit cell parameters obtained from the results of the Rietveld analysis decreased, while the average crystallite size increased with increasing Ni 2+ content. The average microstrain parameters unambiguously showed a change in the spinel structure with cation distribution. Scanning electron 2 microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) analyses were also utilized to characterize the synthesized materials, corroborating the XRPD data. The obtained results indicated that functionalization by starch was successfully achieved.

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To investigate the magnetic behaviour of starch coated cobalt ferrites, ve well established synthetic methods, i.e. co-precipitation, mechanochemical, ultrasonically assisted co-precipitation, microemulsion, and microwave-assisted hydrothermal syntheses were chosen for the materials' preparation. Obtained cobalt ferrites had pure single-phase spinel structures. Scanning and transmission electron microscopy analyses revealed that the morphology of samples is not uniform, and aggregation of individual particles is a dominant process in all cases. Fourier-transform infrared spectra con rmed the presence of starch in all coated samples. The unusually higher magnetization of starch-coated samples than the magnetization of their as-prepared analogs obtained by co-precipitation, ultrasonically assisted coprecipitation and microwave-assisted hydrothermal methods might be explained by the Ostwald ripening mechanism induced by coating process. On the other hand, the decrease of saturation magnetization value was noticed for starch-functionalized nanomaterials synthesized in mechanochemical and microemulsion manner, in comparison to their as-prepared analogs, showing that the size distribution of such nanoparticles is narrow and the average diameter of the grains is near critical for the Ostwald ripening process.

This work is the first report of a very simple and fast one-pot synthesis of nickel oxide (NiO) and hematite (?-Fe2O3) nanoparticles by thermal decomposition of transition metal aqua complexes with camphor sulfonate anions. Obtained nanopowders were characterized by X-ray powder diffraction, Fourier transform IR analysis, scanning electron microscopy, and Energy-dispersive X-ray spectroscopy. X-ray powder diffraction confirmed the formation of high purity NiO and ?-Fe2O3 crystal phases. In the case of ?-Fe2O3, about five times larger average crystallite size was obtained. Fourier transform IR spectra of synthesized materials showed characteristic peaks for NiO and ?-Fe2O3 nanostructures. To visualize the morphology and the chemical composition of the final products Scanning electron microscopy and Energy-dispersive X-ray spectroscopy were performed. The thermogravimetric analysis was done for a better understanding of the general thermal behavior of precursor compounds. This easy-to-perform and fast preparation method opens a broad range of obtained materials? usage, particularly due to its economic viability

To investigate the magnetic behaviour of starch coated cobalt ferrites, five well established synthetic methods, i.e. co-precipitation, mechanochemical, ultrasonically assisted co-precipitation, microemulsion, and microwave-assisted hydrothermal syntheses were chosen for the materials’ preparation. Obtained cobalt ferrites had pure single-phase spinel structures. Scanning and transmission electron microscopy analyses revealed that the morphology of samples is not uniform, and aggregation of individual particles is a dominant process in all cases. Fourier-transform infrared spectra confirmed the presence of starch in all coated samples. The unusually higher magnetization of starch-coated samples than the magnetization of their as-prepared analogs obtained by co-precipitation, ultrasonically assisted co-precipitation and microwave-assisted hydrothermal methods might be explained by the Ostwald ripening mechanism induced by coating process. On the other hand, the decrease of saturation magnetization value was noticed for starch-functionalized nanomaterials synthesized in mechanochemical and microemulsion manner, in comparison to their as-prepared analogs, showing that the size distribution of such nanoparticles is narrow and the average diameter of the grains is near critical for the Ostwald ripening process.