Tailoring the structural, magnetic and dielectric properties in holmium doped Ca-Ba hexaferrite nanoparticles by regulating the Ca-Ba (1:1) concentration for magnetic and electric applications

This work reports the synthesis and characterizations of holmium (Ho) doped Ba-Ca hexaferrites (Ba_0.5Ca_0.5Fe_12-xHo_xO₁₉). Structural analysis confirms the pure hexagonal phase throughout, and morphology shows the uniformly distributed hexagonal-shaped particles. The incorporation of Ho³⁺ ions significantly enhanced magnetic properties, as evidenced by vibrating sample magnetometry (VSM), attributed to the reconfiguration of Fe³⁺ ions and the reinforcement of superexchange interactions. Across all samples, magnetic hysteresis (M−H) loops exhibited a consistent hard ferrimagnetic behavior, with saturation magnetization (M_s) values varying within the range of 28.64 to 36.33 emu/g, remanent magnetization (M_r) from 16.24 to 20.68 emu/g, and coercivity (H_c) from 1.771 to 2.059 kOe, respectively. The composition with x = 0.09 demonstrated the highest M_s, M_r, and H_c values. The dielectric properties underscore the potential applications of fabricated M−type hexaferrites in microwave technology due to their low dissipation factor and ε“, pivotal for minimizing signal attenuation in crucial components such as filters and resonators. Moreover, Ho doped Ba-Ca hexaferrites present promising alternatives to magnets in electric vehicle applications, suggesting avenues for further research and optimization in this domain.