Effect of Fe~(3+)/Ba~(2+) mole ratio on the phase formation and microwave properties of BaFe_(12)O_(19) prepared by citrate-EDTA complexing method

摘要

Barium hexaferrites (BaFe_(12)O_(19)) with various Fe~(3+)/Ba~(2+) 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 Fe~(3+)/Ba~(2+) mole ratio is crucial in phase formation and crystal grain growth. The electromagnetic parameters of epsilon', epsilon", mu', and mu" were determined by network analyzer (Agilent 8722ET) at the frequency range of 2-18 GHz by a reflection/transmission technique. The sample with a Fe~(3+)/Ba~(2+) mole ratio of 11.5 has the lowest permittivity (epsilon' = 1-3, epsilon" approx = 0) and highest permeability (mu' = 1.5-3.5, mu" = 0.5-2.5), exhibiting excellent microwave performances.