Effect of Fe³⁺/Ba²⁺ mole ratio on the phase formation and microwave properties of BaFe₁₂O₁₉ prepared by citrate-EDTA complexing method

Barium hexaferrites (BaFe₁₂O₁₉) with various Fe³⁺/Ba²⁺ mole ratio have been prepared by citrate-EDTA complexing method using citrate and EDTA as complexing chelating agents. DSC analysis, XRD patterns, EDS compositional testing and SEM investigations all display that Fe³⁺/Ba²⁺ mole ratio is crucial in phase formation and crystal grain growth. The electromagnetic parameters of ε′, ε″, μ′, and μ″ were determined by network analyzer (Agilent 8722ET) at the frequency range of 2-18 GHz by a reflection/transmission technique. The sample with a Fe³⁺/Ba²⁺ mole ratio of 11.5 has the lowest permittivity (ε′ = 1-3, ε″ ≈ 0) and highest permeability (μ′ = 1.5-3.5, μ″ = 0.5-2.5), exhibiting excellent microwave performances.