Dynamic Arrays Based on Magnetically Controlled Particles: Synthesis and Application

Abstract

Growth mechanisms of dynamic granular arrays based on magnetically controlled particles are presented. Method of the external rotating magnetic field (ERMF), based on a dipole interaction of magnetic spherical Fe 3 O 4 particles in highly ordered volume arrays is proposed and a design for its practical implementation is developed. The magnetic assembly can result in permanent structures, which could be disassembled on demand by remote demagnetization. To study the interaction field of particles in the arrays, a mean field theory was used and the data were compared with experiment. Reflection spectra of electromagnetic radiation from a volume dense packed array of Fe 3 O 4 particles with thicknesses of 3 and 6 mm, and a flat particles array with a set of 15 and 30 layers, as well as frequency characteristics of attenuation of electromagnetic radiation of the claimed materials in the frequency range from 8.0 GHz to 12.5 GHz obtained. Presented method and the installation have the prospect of being used in the processes of making composite materials for electromagnetic radiation protection using a wide range of materials of micro and nanoparticles.

Enhanced Microwave Absorption and Electromagnetic Properties of Si-Modified rGO@Fe3O4/PVDF-co-HFP Composites

“…Particularly, when the magnetically controlled Fe 3 O 4 nanoparticles are directly packaged on the rGO sheet, these results contribute to optimizing the impedance matching and enhance the EMW attenuation [21,22]. Random Fe 3 O 4 nanoparticle packaging can be difficult to predict, thus making it difficult to obtain composite behavior at a large scale [23,24]. Meanwhile, this charge transfer between rGO and magnetic lossy materials can easily generate the interfacial polarization, dipole relaxation, and magnetic loss [25,26].…”