Refining magnetic characteristics of BaCo2Fe16O27 W-type hexaferrites through Gd3+ substitution for improved microwave potential devices applications

Gd-doped Ba_1-xGd_xCo₂Fe₁₆O₂₇ (BG_xCF) x = (0.00, 0.05, 0.10, 0.15, 0.20, and 0.25) wt.% W-type hexaferrite ceramic pellets were synthesized by ball milling solid-state reaction technique. XRD patterns of the prepared samples verify the single-phase polycrystalline nature without any impurity phase. The doping of Gd ions in the samples impacted the lattice parameters, unit cell volume and bulk density increases. Morphological results analysis using SEM shows the hexagonal plate-like structure of the BG_xCF particles. The increase of Gd contents in the samples created multi-domain structure and grain growth occurred. FT-IR analysis confirmed the existence of the octahedral and tetrahedral vibration of Fe–O, with Gd substitution bond strength between the atom decreases. Raman analysis verifies the existence of A_1g, E_1g and E_2g Raman modes, with Gd wt.% increases there is a red shift of the vibration modes. Magnetic results reveal that with Gd substitution in the BG_xCF samples, the magnetization saturation (M_s) increased for x = 0.05, and 0.10 samples due to strain magnetization, while, for x = 0.15 and 0.20 samples, Ms decreased due to the spinning by Gd ions, and but it is increased for x = 0.25 samples. Moreover, with increases of Gd wt.% in the samples, there is a decrease in the coercive field due to the increase of particle size and a decrease of magnetocrystalline anisotropy. In addition, the dielectric properties revealed increases in both permittivity and dielectric loss with the Gd contents in BG_xCF samples. Permeability studies show the existence of spin resonance phenomena in the samples. The magnetic losses in the Gd-doped samples are higher than the undoped sample due to the decreases of magnetocrystalline anisotropy. The highest values of both dielectric and magnetic losses of the Gd-doped BG_xCF samples make these materials enhance its performance in microwave potential devices applications.