Urea assisted synthesis of Ni1−xZnxFe2O4 (0 ≤ x ≤ 0.8): Magnetic and Mössbauer investigations

- All elements present in EDS spectra indicates the successful formation of urea assisted NiZn spinel ferrite.
- XRD pattern, characteristics bands in FTIR and SAED pattern revealed single phase cubic structure.
- TEM images estimated the particles size as 31-26 nm confirming nanocrystalline nature.
- Coercivity decreases with zinc concentration.
- The distribution of hyperfine fields caused the broadening of the line width.

The system as Ni1−xZnxFe2O4 where x = 0.0, 0.2, 0.4, 0.6 and 0.8 were prepared using sol-gel auto combustion method. A typical as-prepared sample was characterized by using TGA DTA. Then the as-prepared samples were annealed at 600 °C for 6 h in air atmosphere and used for further characterizations. The annealed samples were characterized by XRD, IR, FESEM-EDS and TEM. The magnetic measurements were carried out using pulse field hysteresis loop tracer technique and Mössbauer spectrometer at room temperature. The analysis of XRD patterns favored the formation of the single phase cubic spinel structure of the prepared Ni-Zn spinel ferrite nanoparticles. The structural parameters like lattice constant, crystallite size, X-ray density etc were evaluated using XRD data. The characteristic bands of spinel ferrite for tetrahedral and octahedral sites in IR spectra were observed. The primary analysis of the FESEM images for Ni-Zn spinel ferrite nanoparticles were suggested the agglomerated nature, fine size distribution and spherical geometry. The EDS spectra analysis showed the well matching of calculated and experimentally obtained elemental composition. Moreover, the particle size determination and morphology investigations (x = 0.0 and 0.4) were performed by TEM technique. The particle size obtained is in the order of 28-31 nm which also confirms the nanocrystalline nature of the prepared Ni-Zn spinel ferrite nanoparticles. Using the M − H curves the saturation magnetization, remanence magnetization, coercivity were obtained. Furthermore, other magnetic parameters as remenance ratio, magneton number, anisotropy constant, anisotropy field were determined using M − H data. Moreover, the magnetic investigations of Ni-Zn spinel ferrite nanoparticles were investigated by Mössbauer spectroscopy technique and the isomer shift, line width, hyperfine field, and quadrupole splitting were studied.

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