Tunable Dielectric Property of Fe3O4/SiO2 Meta-composite Fabricated by Magnetic-Field Assisted Self-assembly

In this paper, SiO2 microsphere self-assembly process and heat treatment were combined to prepare Fe3O4/SiO2 meta-composites. XRD, SEM and Precision Impedance Analyzer were used to study the phase composition, microstructure, and dielectric properties of the composites at MHz frequency range. The results show that SiO2 microsphere matrix forms a hexagonal close packing structure and nano-Fe3O4 magnetic particles fill the gap between the close-packed SiO2 microspheres. The results indicate that, in a certain frequency range (1–3 MHz), the dielectric properties of the composites can be tuned by using applied magnetic field to change the distribution of the magnetic particles. But in the other test frequency range, the dielectric properties of the composites show no difference, whether to use magnetic field to control the distribution of the magnetic particles or not.