Optimizing ferroelectric, dielectric, magnetic and strong magnetoelectric coupling through strain engineering in (0–3) types multiferroic composites

In the present study, the eco-friendly magnetoelectric multiferroic (1-x) BaTiO₃-(x) CoFe₂O₄ (0–3) type composites (x = 0.0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1.0) were synthesized using the solid-state reaction method. The average crystallite size and strain induced in the synthesized composites samples were calculated using the Williamson-Hall approach. The Rietveld refinement analysis confirms both phases retain their parent structure. BaTiO₃ phase crystallizes into the tetragonal with P4mm space group, while the CoFe₂O₄ phase exists in cubic with Fd-3m space group. The heterogeneous valence state of Ti³⁺/Ti⁴⁺, Fe²⁺/Fe³⁺ ions, and enhancement in oxygen vacancies stoichiometry ratio were confirmed through the X-ray photoelectron spectroscopy. The distribution of closely packed CoFe₂O₄ grains in the BaTiO₃ matrix was amply demonstrated by the microstructural results. The ferroelectricity of composites drops down due to fluctuations in the state of Fe²⁺/Fe³⁺ ions that enhance the leakage current of the composite sample. The observed dielectric relaxation phenomena in the composites are explained by the electron hopping mechanism, which also accounts for the higher dielectric constant (ε′). With an increase in the CoFe₂O₄ weight percentage, the magnetic moment is found to be 8 emu/g for 80 % of CFO based composites. For 50 and 60 mol % CFO, the highest observed values of α_ME are 22.63 mV/cm. Oe and 17.56. mV/cm. Oe respectively. These composites may be investigated for magnetic sensor and ME memory device applications due to the strong ME interaction and significant value of self-biased α_ME.