Abstract:
Microwave materials with outstanding absorbing power and low cost are decisive for the electromagnetic issues in stealth technology. In the present work, Dy-Gd substituted YIG nano ferrites having Y3_x-yDyx GdyFe5O12; (whereas x = 0.00, 0.025, 0.05, 0.075, 0.10; y = 0.00, 0.25, 0.50, 0.75, 1.00), were prepared by two-step sol-gel self-ignition route for absorption purpose. Rare earth cations such as Dy-Gd effects on the structural, and elec-tromagnetic characteristics of YIG were evaluated. Different characterizations like XRD, FESEM, and VSM were used to evaluate the physicochemical and electromagnetic properties of the Dy-Gd co-doped YIG ferrites. A high-frequency vector network analyzer evaluated dielectric measurements such as real and imaginary permittivity and permeability, ac-conductivity, and dielectric loss of the Dy-Gd doped YIG ferrites. Dy-Gd doped YIG ferrites samples depicted single phase cubic garnet structure. Cation distributions of Dy-Gd doped YIG ferrites were also calculated. FESEM images revealed a homogeneous, closely packed grain size distribution of the Dy-Gd doped YIG samples. Magnetic properties such as saturation magnetization, remanence, coercivity, initial permeability, magnetic anisotropy constant, and Bohr magneton were also investigated using magnetic hysteresis loops and the SFD and high-frequency evaluations. Dielectric properties such as dielectric losses, ac conductivity, permeability, and permittivity of the Dy-Gd doped YIG samples show high values at x = 0.075 and y = 0.75. Metamaterial-based Dy-Gd doped YIG absorbers were designed and simulated in the CST software. The resonance peaks depicted the absorption at 3.6 GHz with absorptivity of 67 %, 75 %, and 85 % for x = 0.00-y = 0.00, x = 0.05-y = 0.5, and x = 0.075-y = 0.75, respectively. High saturation magnetization, low coercivity, and extraordinary dielectric absorption characteristics of Dy-Gd doped YIG ferrites make them appropriate for absorption, and EMI shielding applications in microwave regime.
