M2+, 3+ (M = Mn3+, Zn2+, Ni2+)이 치환된 Sr3Co2Fe24O41 hexaferrite 복합체의 전자기파 흡수 특성

Mn, Zn, Ni-substituted Z-type hexaferrites, Sr3Co2Fe24O41 (Sr3Co2Fe24-xMnxO41, Sr3Co2-yZnyFe24O41,Sr3Co1-zNizZnFe24O41), were prepared by sol-gel synthesis processes and their high-frequency magnetic,dielectric and electromagnetic (EM) wave absorption characteristics were investigated. Substituting Mn forFe by x = 0.5 maintained the single-phase Z phase while shifting the  , μ″ spectra towards lower frequencies. Substituting Zn for Co by y = 1.0 resulted in the single-phase Z phase and effectively shifted the  , μ″ spectratowards lower frequencies. Additionally, substituting Ni by z = 0.5, 1.0 gradually shifted the  , μ″ spectratowards higher frequencies. The Sr3Co2Fe24O41 with a single Z-type hexaferrite phase and epoxy (10 wt.%)composite showed strong ferromagnetic resonance (FMR) at 3.05 GHz and exhibited primary and secondarystrong EM wave absorption characteristics at the thicknesses where impedance matching occurred near theFMR frequency and at frequencies higher than this. Substitution of Mn and Zn tended to decrease the FMRfrequency, while substitution of Ni tended to increase it. The samples with substituted compositions alsoshowed changes in the primary and secondary strong EM wave absorption frequency regions, depending onthe FMR frequency changes. They demonstrated excellent EM wave absorption performance with the absolutevalue of the minimum reflection loss (RLmin) ranging from 42 to 58 dB. The FMR-tunable Z-type hexaferriteis a promising EM wave absorption material that can modulate EM wave absorption characteristics by cationsubstitution in in L-S-band (1~4 GHz) and X-band (8~12 GHz) ranges.