Structural, Magnetic, Dielectric, and Ferroelectric Properties of CoFe₂O₄-BaTiO₃ Nanocomposites

Nano-size spinel ferrite CoFe₂O₄ (CFO), ferroelectric BaTiO₃ (BTO), and their nanocomposites BTO@CFO (BTO nanoparticles are added during the synthesis of CFO) and CFO@BTO (CFO nanoparticles are added during the synthesis of BTO) were synthesized using a combination of chemical co-precipitation and sol–gel routes, respectively. The phase formation and crystallinity of the bare CFO and BTO and their nanocomposites were verified via x-ray diffraction (XRD) patterns. High-resolution transmission electron microscopy (HRTEM) revealed the formation of the nanocomposites. Magnetization measurements confirmed the ferromagnetic behavior of all the samples except BTO, in which superposition of a weak ferromagnetic and diamagnetic response occurred due to its nanostructure. Magnetization versus temperature (M–T plot) measurements showed an anomaly near the ferroelectric-to-paraelectric phase transition of BTO. Also, the dielectric constant (ε′) and loss tangent (tanδ) with respect to frequency (10²–10⁶ Hz) and temperature (300–700 K) were examined. The ε′–T curve of the nanocomposites exhibited an anomaly at the same temperature as observed in the M–T plot, indicating the inherent magnetoelectric coupling in the nanocomposites. The energy storage properties of BTO and the nanocomposites were examined via P–E loop analysis and confirmed that the CFO@BTO sample exhibits maximum energy storage efficiency.