WOWS Sol–Gel Based Synthesis and Structural, Morphological, Electrical and Magnetic Characterization of Co-Sm Doped M-Type Barium Hexaferrite Materials

Abstract

Cobalt-samarium (Co-Sm) doped M-type barium hexaferrite nanocrystalline materials (BaFe12-2ZCoZSmZO19) of various compositions (Z = 0.0, 0.2, 0.4, 0.6) were prepared via without water and surfactants (WOWS) sol–gel approach. X-ray diffraction (XRD) studies were employed to elucidate the structural properties. For each composition, the porosity, theoretical density, crystallite size and lattice constant were obtained from XRD data. The dielectric parameters were measured by LCR meter. A scanning electron microscope (SEM) was used to investigate the morphology of materials. DC electrical resistivity (ρdc) calculations were performed in a broad range of temperature (from 100°C to 400°C). The activation energy (ΔE) was also calculated from electrical resistivity data. The vibrating-sample magnetometer studies were employed to investigate hysteresis loops and magnetic properties were estimated from hysteresis curves. It was observed that the materials were of high magnetocrystalline anisotropy, large Curie temperature, high value of magnetization and excellent dielectric characteristics. The XRD spectrum analysis of materials disclosed that the structure of materials was hexagonal. The SEM investigations revealed that the materials are uniform in both shape and size, with a normal size ranged from 295 nm to 440 nm. Electrical resistivity of materials disclosed their dependence on the temperature, which suggests the semiconducting nature of M-type hexaferrites. The magnetic characteristics were evaluated at 25°C and they showed typical hysteresis loop demonstrating ferromagnetic nature of the compounds. The results of Sm3+ and Co2+ ions substitution expose the large values of coercivity (Hc), which indicates the nanocrystalline nature of the materials.