Optimized Magnetodielectric Coupling on High-Temperature Polymer-Based Nanocomposites

CoFe2O4 (CFO) ferrite nanoparticles with an average size of 15 nm were synthesized by a hydrothermal method and used to develop magnetodielectric (MD) composites with the piezoelectric copolyimide 2CN/0CN as polymer matrix. It is shown that the dielectric constant, dielectric loss, and saturation magnetization values of the composites increase with the increasing CFO content, being 4.4, 0.01, and 12 emu·g–1, respectively, for the sample with 20 weight percentage (wt %) of ferrite. Additionally the large MD effect response (MDE(%) = 10.15) and magnetodielectric coefficient (γ = 5.8 × 10–2) allow a new physical insight into the magneto-mechano-electrical interaction between magnetostrictive CFO and the polymer matrix. Such high MD response, the highest reported for polymer-based composite materials, can support innovative applications in the areas of sensors, actuators, and filters, among others.