Cu²⁺/Dy³⁺ dual doped calcium based Ca_1-xCu_xFe_12-xDy_xO₁₉ hexaferrites: Microstructural and magnetic properties for magnetic applications

The structural and magnetic behaviour of hexaferrite can be significantly altered by varying the sintering temperature and cationic subtitutions. Therefore, using the sol–gel route, we have synthesized M−type Ca_1-xCu_xFe_12-xDy_xO₁₉ (x = 0.0, 0.05, 0.10, 0.15, 0.20) hexaferrite nanoparticles in the present research work. The samples' microstructure, phase, and magnetic characteristics are examined concerning different doping concentrations using SEM, XRD, and VSM. The analysis indicates a minor percentage of Fe₂O₃ phases in all samples. The refined lattice variables ‘a’ and ‘c’ are initially enhanced by increasing the level of doping upto x = 0.15 and then decreases. Similarly, the average crystallite size shows an increase continuously. The remanence and saturation magnetization rise first as the doping level increases, then show a minor change for the maximum doping level. Like this, as the doping content is raised, the coercivity and magneto-crystalline anisotropy field increased first and then showed a minor decrease. The sample with the best magnetic properties is Ca_0.85Cu_0.15Fe_11.85Dy_0.15O₁₉ with M_s = 35.738 emu/g, m_B(µ_B) = 6.732B, M_r = 20.430 emu/g, H_c = 3.15 kOe, and M_r/M_s = 0.572. All samples were excellent candidates for use in magnetic devices due to their high Mr/Ms values. The effect of doping on the magnetic features of M−type hexa-ferrites has made them useful in numerous applications, such as high-performance self-biased circulators, magnetic filters, and storage devices.