Micro-structural characterization and magnetic study of Ni1.5Fe1.5O4 ferrite synthesized through coprecipitation route at different pH values

• Published in: Materials chemistry and physics 2014-07, Vol.146 (1-2), p.159-169
• Main Authors: Aneesh Kumar, K.S., Bhowmik, R.N.
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Fourier transform infrared spectroscopy (FTIR); Magnetic materials; Microstructure
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2014.03.015

We report the synthesis, structural and magnetic properties of Ni1.5Fe1.5O4 ferrite nanoparticles. The pH value during coprecipitation from metal nitrates solution has been varied in the range 1–12. The samples after coprecipitation have been annealed at different temperatures to study thermal effect on crystalline phase and grain growth process. A detailed microstructural study has been performed using X-ray diffraction (XRD), Fourier Transform Infra-red Spectroscopy (FTIR), Scanning electron microscopy (SEM) attached with Energy dispersive analysis of X-ray (EDX) spectrometer, and Micro Raman Spectroscopy. XRD pattern showed formation of single phased cubic spinel structure above certain annealing temperature that strongly depends on the pH value during coprecipitation. Analysis of the FTIR and Raman spectra of the samples prepared at different pH values indicated ordering of cations in A and B sites of the cubic spinel structure. EDX data indicated Ni deficiency for the samples prepared at pH 2. Minor hematite (α-Fe2O3) phase has been identified for the samples coprecipitated at pH 4 and 6, in addition to the major cubic spinel phase. The samples of Ni1.5Fe1.5O4 have shown soft ferromagnetic character at room temperature and ferromagnetic parameters varied in a wide range with pH value at which sample was coprecipitated. [Display omitted] Variation of lattice parameter with annealing temperature (a) and pH values (b) for samples prepared at specific pH and annealed at specific temperature, respectively, variation of crystalline size with annealing temperature (c) and pH values (d) for samples prepared at specific pH and annealed at specific temperature, respectively. Inset of (c) shows a typical example of the linear fit to calculate crystalline size of NFpH8_800 sample. •Report on synthesis, structure and RT ferromagnetism of Ni1.5Fe1.5O4 ferrite.•Nanoparticles prepared by varying pH in the range 1–12 during coprecipitation.•Detailed microstructure using XRD, SEM, FTIR and Raman spectroscopy.•Soft ferromagnetic properties in ferrite has been tuned by varying pH value.