Microstructural, magnetic and dielectric performance of rare earth ion (Sm³⁺)-doped MgCd ferrites

The combined effects of Sm^3+ substitution together with the addition of 3 wt% Bi_2O_3 endow MgCd ferrites with excellent magnetic permeability and dielectric permittivity. Various concentrations of Sm^3+ (x = 0, 0.03, 0.06, 0.09, 0.12 and 0.15) were employed to modify the permeability (\mu') and permittivity (\varepsilon') of the MgCd ferrites. X-ray diffraction, scanning electron microscopy (SEM), vibrating sample magnetometry and vector network analysis techniques were used to characterize the samples. The measurement results reveal that the ferrites processed a saturation magnetization of up to 36.8 emu/g and coercivity of up to 29.2 Oe via the conventional solid-state reaction method. The surface morphology SEM confirms that with increasing Sm^3+ concentration, the grain shape changes from a polygon to a circle. Moreover, the dielectric permittivity can reach a value of 23. The excellent properties obtained in Sm^3+-substituted Mg ferrites suggest that they could be promising candidates for modern high-frequency antenna substrates or multilayer devices.