A Study of Structural, Magnetic and Various Dielectric Parameters of Ca-Substituted W-Type Hexaferrites for Applications at 1–6 GHz Frequencies

Abstract

Single phase Ca-substituted W-type hexaferrites Sr1-xCaxZn2Fe16O27(x = 0.00(0.25)1.00) have successfully been synthesized by using sol–gel self-combustion at 1300°C. These hexaferrites are investigated by x-ray difrractometry (XRD), scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and vector network analysis. XRD analysis confirms the formation of a single W-type hexaferrites phase. The DC electrical resistivity increases with incrementing Ca contents. The morphology of all the hexaferrites shows hexagonal platelet-like structure. The prepared ferrites depict soft magnetic nature with high saturation magnetization, low coercivity and enhanced magnetic moments. The complex parameters such as complex permittivity and permeability decrease with the increasing Ca content. The prepared samples show good quality factor of 3 at 6 GHz, AC conductivity changes from 0.9 S/m to 0.5 S/m, and tangent loss decreases from 0.5 to 0.34 with Ca substitution. These improved characteristics make these hexaferrites valuable for devices such as microwave absorbers operated at higher frequencies.