Structural, magnetic and dielectric features of Cu, Al substituted Ca-hexaferrites for magnetic and energy applications

The sol–gel method was used in our work to develop Ca_1-xCu_xFe_12-xAl_xO₁₉ (x = 0.0, 0.05, 0.10, 0.15, 0.20) hexaferrites nanoparticles. The microstructure, phase, and magnetic characteristics of the samples were examined relative to different doping concentrations using SEM, XRD, and VSM techniques. The analysis indicates the presence of Fe₂O₃ phases in all samples. The lattice parameters ‘a’ and ‘c’ were initially reduced and then enhanced with doping level. Similarly, the average crystallite size showed a decline continuously. The remanence as well as saturation magnetization both decline first with the doping level and then rise after reaching their minimum values at x = 0.15. Analogously, as the doping level is raised, the coercivity as well as magneto-crystalline anisotropy field first declines and then increases. The sample with the best magnetic properties is Ca_0.85Cu_0.15Fe_11.85Al_0.15O₁₉ with M_s = 27.954 emu/g, m_B(µ_B) = 5.117B, M_r = 15.676 emu/g, M_r/M_s = 0.577, H_c = 2.726 kOe, and H_a = 0.852 kOe. Dielectric properties suggested the decrease in loss and enhancement in the dielectric constant. Results recommend that M-type hexagonal ferrites could be well adjusted for numerous magnetic usages such as magnetic filters, storage devices and high-performance self-biased circulators and energy applications.