Enhanced Structural and Dielectric Properties of Calcium and Chromium-Based M-Type Hexagonal Ferrites with Polyvinyl Alcohol (PVA) Polymer Composites

Abstract

[Formula: see text]-type hexagonal ferrites with compositions Ca[Formula: see text]CrxFe[Formula: see text]O[Formula: see text] at ([Formula: see text], 0.2, 0.3, 0.4, 0.5) were successfully prepared by sol–gel auto combustion method and then immersed with polyvinyl alcohol (PVA) by ultrasound-assisted in situ emulsion technique. The results indicate that the synthesized nanoparticles were diffused homogeneously in PVA retaining the size and shape of the particle. The single-phase [Formula: see text]-type hexagonal structure was revealed by X-ray diffraction (XRD) with extra 101 peak of PVA at 2[Formula: see text]. The suitable signal-to-noise ratio in the high density recording media can be achieved due to the small particle size of the prepared composites as compared to pure hexaferrites. The interaction between PVA and nanoparticles was confirmed by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) images revealed the homogeneous distribution of grains, the crystallite size was measured from SEM (25–38[Formula: see text]nm), and it is also in agreement as calculated from the Scherer formula. Dielectric properties were also explored in the range of 1 MHz–3 GHz frequencies. Dielectric constant and dielectric loss were found to decrease with increasing frequency and decrease with the addition of ferrite ratio in the polymer matrix. This impact is because of the grain boundary at low frequency regime. The occurrence of resonance at high frequency regime recommends the investigated samples for multilayer chip inductor.