Evolution of nano-sized hexagonal ferrites suitable as permanent magnets and for high frequency applications

Abstract

The impact of V2+ substitution on structural, optical, electrical, and dielectric behavior of T-type hexaferrite Ca2-xVxFe8O14 (x = 0.0, 0.4, and 0.6) fabricated utilizing sol-gel auto-combustion followed by sintering at 1100 °C is reported in current investigation. XRD analysis was used to validate the single phase formation, which resulted in computation of lattice parameters, unit cell volume, and X-ray density. Furthermore, the microstructural strain was calculated by utilizing Williamson-Hall method. According to Koop's hypothesis, the dielectric constant reduced with the increment in frequency while increased with V2+ replacement. The tiny polarons mechanism helped to explain the increase in the ac-conductivity with frequency. Using cole-cole representation, active contribution of grains and grain borders in distinct frequency areas was elucidated. The polarization verses electric field hysteresis loops demonstrated the resistive nature of samples. Transmission electron microscopy indicates a platelet-like shape of particles and UV–Vis spectroscopy revealed that the bandgap varied in the region of 4.31–4.37 eV. Magnetic studies unveiled the increment in saturation magnetization and reduction in coercivity with V2+ replacement. All of these findings suggest that these compositions could be used in high-frequency operating devices and magnetic storage systems.