Structural, magnetic and electromagnetic properties of SrFe12O19 ferrite with particles aligned in a magnetic field

Abstract

Plate-like hexagonal SrFe12O19 particles were synthesized by hydrothermal process. The as-synthesized particles were dispersed evenly in epoxy resin and then took root in the curing epoxy matrix under a uniform magnetic field. The microstructures, morphologies, magnetic and electromagnetic properties of the composites were studied. The plate-like particles were arranged with the plates perpendicular to the field direction. This demonstrated that the easy axis of the particle was perpendicular to the plate. There were obvious differences in remanent magnetization (Mr) among the aligned sample with the plates parallel to the testing direction (parallel sample), the aligned one with the plates perpendicular to the testing direction (perpendicular sample), and the nonaligned one (nonaligned sample). The perpendicular sample was better at storage capacity of electric and magnetic energy than the others. This indicated both the polarization and domain wall displacement were different between the easy axis direction and the hard axis one. The parallel sample caused maximum dielectric loss and the perpendicular sample caused minimum dielectric loss in the frequency range 2–12 GHz and 14.4–18 GHz, while it was reverse in the frequency range 12–14.4 GHz. The nonaligned sample caused maximum magnetic loss in the low frequency range, while the aligned samples were not superior at magnetic loss in the whole frequency range.