Study of structural, dielectric, and magnetic properties of nickel doped strontium hexaferrite nanoparticles for microwave absorption application

This study presents the fabrication of nickel-doped strontium hexaferrite nanoparticles using a sol-gel auto-combustion technique. A compositional series of Sr₁₋ₓNiₓFe₁₂O₁₉ (x = 0.00, 0.20, 0.35, and 0.50) was developed to explore the influence of Ni incorporation.Structural analysis confirmed the successful formation of M-type hexaferrite phases through lattice parameter evaluation. Crystallite sizes, determined via the Scherrer equation, were found to range between 29 and 39 nm. FTIR spectroscopy was employed to investigate atomic-scale vibrational modes, revealing distinct absorption bands corresponding to tetrahedral and octahedral coordination sites. Magnetic behavior, assessed using a vibrating sample magnetometer (VSM), displayed enhanced saturation magnetization values, rising from 37.26 to 44.12 emu/g upon substitution withNi at x = 0.50. All samples exhibited effective electromagnetic wave absorption in the Xband (8-12 GHz), with a notable maximum reflection loss of -22.50 dB at 9.26 GHz for the x = 0.50 composition. At this frequency, the normalized input impedance (Zin/Zo) was approximately 0.8, indicating a strong impedance match and superior microwave absorption capability. These findings position the synthesized materials as promising candidates for advanced microwave absorber technologies.