Hybrid Magneto-Responsive Composites Made from Recyclable Components: Tunable Electrical Properties Under Magnetic and Mechanical Fields

This study presents the fabrication and characterization of hybrid magneto-responsive composites (hMRCs), which are composed entirely of recyclable components: magnetite microparticles (MMPs) as fillers, lard as a natural binding matrix, and cotton fabric for structural reinforcement. MMPs are obtained by in-house plasma-synthesis, a sustainable, efficient, and highly tunable method for producing high-performance MMPs. The resulting hMRCs are integrated into flat capacitors, and their electrical capacitance (C), resistance (R), dielectric permittivity (ϵ′) and electrical conductivity (σ) are investigated under a static magnetic field, uniform force field and an alternating electric field. The experimental results reveal that the electrical properties of hMRCs are dependent on the volume fractions of MMPs and microfibers in the fabric, as well as the applied magnetic flux density (B) and compression forces (F). C shows an increase with both B and F, while R decreases due to improved conductive pathways formed by alignment of MMPs. σ is found to be highly tunable, with increases of up to 450 % under combined field effects. In the same conditions, C increases up to 60 %, and R decreases up to 80 %. Thus, by employing plasma-synthesized MMPs, and commercially available recyclable lard and cotton fabrics, this study demonstrates an eco-friendly, low-cost approach to designing multifunctional smart materials. The tunable electrical properties of hMRCs open new possibilities for adaptive sensors, energy storage devices, and magnetoelectric transducers.