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Barium titanate nanoparticles were synthesized via a low temperature sol-gel technique using acetylacetone as a chelating agent. The X-ray diffraction pattern confirmed the formation of tetragonal perovskite structure of the material. The average crystallite size was found to be 49 nm using the Debye-Scherrer method. The Williamson–Hall plot was drawn for evaluating the micro-strain and crystallite size. Raman spectroscopic features typical for the tetragonal phase were identified for Barium titanate powder. In addition to these, an absorption band edge and an optical bandgap were found to be of 406 nm and 3.14 eV respectively. Barium titanate displays polychromatic luminescent peaks in UV -visible regions and it was attributed to the near-band-edge transition and defect states in the optical band gap of the perovskite structure. [ABSTRACT FROM AUTHOR]

Nickel ferrite NiFeO nanoparticles (NPs) were successfully synthesized by using nickel nitrate, ferric nitrate, citric acid, and ethyl cellulose as a surfactant by a simple sol-gel-assisted combustion method (SACM) and microwave-assisted combustion method (MACM). Structural, morphological, optical, and magnetic properties of the obtained powder were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), photoluminescence (PL) spectroscopy, and vibrating sample magnetometry (VSM). XRD results show that the resultant powder was pure crystalline with cubic structure. The average crystalline size was found to be 18.8 and 10.2 nm synthesized by SACM and MACM, respectively. FT-IR spectra indicate the type of bonds between Ni-O and Fe-O (metal and oxygen). SEM images show that the morphology of the powder consists of well-defined structure. VSM results showed a ferromagnetic behavior of the sample. Antimicrobial activity of NiFeO nanoparticles was performed. Both sample 1 (SACM) and sample 2 (MACM) show good inhibition in the zone 100 μg/ml. While comparing, sample 2 shows high inhibition than sample 1. [ABSTRACT FROM AUTHOR]

A comparative investigation of the structural, optical, and magnetic properties of NiFe 2 O 4 (NFO) and ZnFe 2 O 4 (ZFO) spinel nanoparticles were synthesized by microwave combustion method. X-ray diffraction (XRD) showed that the ZFO spinel nanoparticles formed a cubic structure, but the NFO spinel nanoparticles formed with additional Fe 2 O 3 in them. The average crystallite size was observed to be in the range 16–20 nm. X-ray photoelectron spectroscopy (XPS) peak areas are often used to quantify the elemental compositions and oxidizing states of NFO and ZFO spinel surfaces. The appearance of FT-IR bands at around 548, 514 and 649 cm−1 were correlated to the Fe–O and Zn/Ni–O stretching modes of cubic NFO and ZFO structure. The direct band gap estimated using Kubelka–Munk (K–M) method to obtain by the NFO is 3.35 eV and ZFO is 2.13 eV respectively. The surface morphology revealed nanosized crystalline grains with agglomerate separated particles that are like spherical/non-spherical forms and fused grain boundaries. Magnetic measurements of NFO and ZFO spinel nanoparticles showed ferromagnetic behavior at room temperature. [ABSTRACT FROM AUTHOR]