Microwave Absorption Properties of Polymer Modified Ni-Zn Ferrite Nanoparticles

Abstract

Polymer composites of magnetic particles are widely used as microwave absorbers. An effective method for obtaining thinner microwave absorbers for device design is increasing the volume fraction of magnetic nanoparticles by enhancing the permeability of composites. In this study, composites were prepared using Ni-Zn ferrite nanoparticles surface-modified with 4-META (4-methacryloylioxyethyl trimellitate anhydride) and cross-linked with PEG-4SH (pentaerythritol tetra-polyethylene glycol ether with four thiol-modified terminals). These composites have a high volume fraction of nanoparticles (up to 72 vol%) and permeability (μ_{r max}″=5.9). In addition, the prepared composites showed good microwave absorption properties (R.L.<−20 dB) with a smaller matching thickness than conventional microwave absorber using spinel-type ferrite.