Nanocomposites and nanomaterials

Novel method for synthesis and characterization of Ni–Zn ferrite nanoparticles
Plutenko M.O.1, Plutenko T.O.2, Fedorchuk O.P.2
1 Faculty of Chemistry, Taras Shevchenko National University of Kyiv. Lva Tolstoho Street, 12, Kyiv-01033, Ukraine. 
2 Solid State Chemistry Department Faculty of Chemistry, V.I. Vernadsky Institute of General and Inorganic Chemistry of the NAS of Ukraine. Akad. Palladin ave, 32/34, Kyiv-03142, Ukraine. 
E-mail: taplutenko@gmail.com

Nanoparticles of the Ni1-xZnxFe2O4 system (where 0 ≤ x ≤ 1), were synthesized using urea and microwave radiation. The obtained samples were characterized by TGA and DTA. Then heat treatment was carried out at 500 °C for 4 hours in an air atmosphere. The obtained nanoparticles were characterized by XRD, FESEM-EDS, TEM, and FTIR methods. Magnetic characteristics were measured using a vibrating magnetometer LDJ-9500 and samples were compressed into tablets, at the temperature of 20 °C and a magnetic field of 3.98 kA/m. Mossbauer spectra were obtained using a dynamic type spectrometer operating in the mode of constant acceleration. 57Co in the Cr matrix was used as a source of γ-quanta. Measurements were performed at the temperature of 20 °C.
X-ray powder diffraction analysis showed the formation of a single-phase cubic structure of Ni-Zn ferrite spinel. Structural parameters such as lattice constant, crystallite size were estimated using XRD data. Characteristic bands for tetrahedral and octahedral regions of spinel were observed in the FTIR spectra. FESEM image analysis for Ni-Zn ferrite nanoparticles showed spherical geometry, fine size distribution, and agglomeration of nanoparticles. Analysis of EDX spectra showed good consistency of the calculated and experimentally obtained elemental composition. In addition, particle size determination and morphology studies were performed by the TEM method. The obtained particle size was about 27-34 nm for Ni0.5Zn0.5Fe2O4, which also confirms the nanocrystalline nature of the prepared nanoparticles of Ni-Zn spinel system. Zinc content leads to an increase in the size of nanoparticles and crystal cell volume. The magnetic properties change with increasing Zn concentration. The highest value of magnetic saturation is observed for ferrite Ni0.5Zn0.5Fe2O4. In the Mossbauer spectrum at room temperature for the Ni0.5Zn0.5Fe2O4 sample, two sextets are observed, which are associated with the presence of two different local structures in the material.