Substituted Lithium Ferrite Utilized as Magnetically Active Filler for Composites with Acrylonitryle Butadiene Rubber Matrix

Soft magnetic lithium ferrite (Li0.525Zn0.30Ti0.35Fe1.825O4) with a small addition of Bi and Mn prepared by wet self-propagating combustion method was used as magnetically active filler in elastomeric composite materials with the content 17 to 45 vol%. XRD analysis confirmed single-phase cubic spinel structure of synthesized ferrite with average crystallite size of 38 nm. The magnetic characteristics specified from measured hysteresis loops and from the temperature dependences of magnetic susceptibility confirmed soft magnetic behavior of Li ferrite with good rectangularity. The effect of magnetic filler concentration on various magnetic and microwave absorption properties of magnetic polymer composites was investigated, and assessed from complex permeability measurements in the frequency range of 1 MHz to 6.5 GHz. Adding more filler increases the magnetic permeability while the resonance frequency decreases.