Impact of nickel substitution on structure, magneto-optical, electrical and acoustical properties of cobalt ferrite nanoparticles

In this study, we have investigated the impact of nickel substituted cobalt ferrite nanocrystals, which were synthesized by a facile co-precipitation technique. The various physical properties such as structural, electrical, magneto-optical and thermal were studied. These properties were characterized using XRD (X-ray diffraction), FT-IR (Fourier-transform infrared spectroscopy), VSM (vibrating sample magnetometer), UV-visible (Ultraviolet-visible) spectra, LCR (Inductance capacitance resistance) meter and photoacoustic spectrophotometer, respectively. From XRD analysis, single face cubic structure (Fd3m) was determined. It was found that as the nickel substitution increased, the crystallite size (D) was decreased from 17.4 +/- 1.7 nm to 6.7 +/- 1.2 nm. Various structural parameters such as oxygen positional parameters, bond length and cation distribution were determined. Using FT-IR technique, various types of interionic bonds and the elastic properties with their distribution of ions in the formation of spinel phase was found between 400 and 600 cm(-1) for the as-synthesized nanocrystals. The aspect of morphology was determined using TEM (transmission electron microscopy). Surface analysis for the as-synthesized products was found to increase from about 41.8 +/- 0.6 m(2)/g to around 92.7 +/- 2.1 m(2)/g with the increase in concentration of Ni ions. From UV-visible spectrum, empirical relation was calculated which indicates the nature of nano crystallinity of the as-synthesized sample. The electrical properties of the as-synthesized samples were premeditated by utilizing LCR meter; at a function of frequencies (10 Hz -10 MHz) at room temperature (RT) impedance was analyzed. Impedance study confirmed that the as-synthesized sample with major grain boundary contributes to conduction. The product with x = 0.9 shows a low dielectric loss and high dielectric constant and henceforth it can used in electromagnetic devices with high frequency. The hysteresis loop elucidates a steadily decrease in Bohr magneton and saturation magnetization, which indeed exhibited a non-linear conduct, where else we could observe a significant increase of anisotropy constant. The thermal properties such as diffusivity, conductivity and effusivity were determined using photoacoustic spectrophotometer and it was found that highly substituted nano-sample has high thermal stability when compared to the other concentrations. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The physical properties of nickel substituted cobalt ferrite nanocrystals were investigated in this study, including structural, electrical, magneto-optical, and thermal properties. Various techniques such as XRD, FT-IR, VSM, UV-visible spectra, LCR meter, and photoacoustic spectrophotometer were used for characterization. Increasing nickel substitution led to a decrease in crystallite size and an increase in surface analysis of the synthesized products, making them suitable for high-frequency electromagnetic devices.