Correlation between the multiferroic properties in (1-x)BaTiO₃-xCoFe₂O₄ composites

Multiferroic materials, which exhibit coupled ferroelectric and magnetic properties, hold immense promise for multifunctional device applications. Here, a multistep synthesis method, involving chemical synthesis, mechanical milling, and Spark Plasma Sintering, was utilized to fabricate (1-x)BaTiO₃-xCoFe₂O₄ (BTO-CFO) compacted ceramics composites with x = 0.1, 0.2, 0.3, and 0.4. Controlled high pressure and pulsed current facilitated rapid densification, yielding high-density fine microstructures. Structural analysis confirmed the coexistence of tetragonal BaTiO₃ (BTO) and cubic spinel CoFe₂O₄ (CFO) phases, forming 0–3 type multiferroic composites. Microstructural analysis revealed CFO grain clustering within the BTO matrix. The temperature-dependent magnetization curve of CFO shows an increase in magnetization within the temperature range of BTO ferroelectric phase transition, suggesting a strain-mediated magnetoelectric coupling. Temperature and frequency dependence of dielectric permittivity highlighted significant CFO conductivity contribution. Ferroelectric hysteresis and magnetoelectric coupling were observed predominantly in low CFO content samples, with differences in magnetoelectric coefficient values attributed to preferential ferroelectric polarization alignment. Our findings suggest that achieving high interface coupling is very challenging due to high leakage current from the magnetic phase.