Exploring the structural and optical modifications induced by Ru doping in Ba0.5Sr0.5RuxFe12-xO19 M-type hexaferrites to enhanced microwave absorption

This study reports the effects of Ru doping on the structure, optical and microwave absorption (MWA) properties of M-type hexaferrites (MHF) for potential applications in electromagnetic interference (EMI) shielding and stealth technology. The Ba0.5Sr0.5RuxFe12-xO19 (x = 0.00,0.05,0.10,0.15 and 0.20) materials were synthesized using a sol-gel auto-combustion method, and their structural and morphological characteristics were analyzed using XRD, FESEM, and EDAX. The Rietveld refining method confirmed the stability of a hexaferrite structure belonging to the P63/mmc space group. The FESEM analysis of prepared hexaferrite materials revealed well-organized structures with particle sizes ranging from 0.63 mu m to 5.12 mu m. EDAX confirmed the presence of Ba, Sr, Ru, Fe, and O, indicating the purity of the synthesized MHF. PL spectroscopy showed that increasing the doping of Ru decreased PL intensity due to non-radiative recombination. Rua+ doping gives rise to a prominent emission peak at 578 nm, an increase in the band gap energy from 2.58 eV to 2.83 eV and improved microwave absorption properties, with a minimum reflection loss (RL) of-34.4 dB at 10.08 GHz for x = 0.15. The work demonstrates the synergistic role of Rua+substitution in enhancing dielectric properties, magnetic loss mechanisms, and impedance matching, making these materials ideal candidates for tailored electromagnetic wave absorption in the 8-12 GHz frequency range. The material thickness plays a crucial role, with thinner samples exhibiting better microwave absorption at higher frequencies and thicker samples performing more effectively at lower frequencies, making prepared MHFs suitable for electromagnetic interference (EMI) shielding.