Magneto-electric coupling and improved dielectric constant of BaTiO3 and Fe-rich (Co0.7Fe2.3O4) ferrite nano-composites

(x)BaTiO3-(1-x)Co0.7Fe2.3O4 (BTO-CFO) magnetoelectric nanocomposite ceramic with x=0.0, 0.25, 0.50, 0.75, 1.00 were successfully designed and fabricated by sol-gel route. The structural, micro structural, dielectric, ferromagnetic, ferroelectric and magnetoelectric properties of these composites were investigated. The coexistence of tetragonal phase and cubic spinel phase, without any secondary phase in composites is confirmed by the X-ray diffraction measurement. The field emission scanning electron micrograph show well distributed ferrite and ferromagnetic phases in the composites. The energy dispersive X-ray results revealed the purity and stoichiometry of BTO-CFO nanocomposites. The dielectric constant and loss factor of the composites were studied as a function of frequency. The composite sample with x=0.50, results in higher value of dielectric constant whereas CFO possess lowest value of dielectric constant. The magnetization hysteresis (M-H) loop of the composites show ferromagnetic behavior with saturation magnetization values, Ms varies from 15 to 67.68 emu/g and coercive field Hc from 1538 to 1862 Oe. All the composites exhibit typical ferroelectric hysteresis loops indicating the presence of spontaneous polarization. The magnetoelectric voltage coefficient increases linearly with increases in applied d. c. magnetic bias field up to 8 KOe. The maximum value of magnetoelectric voltage coefficient, alpha(ME) = 7.7 mV/cm Oe for BTO-CFO composite having 25% ferrite and 75% ferroelectric content. The high ME voltage coefficient of BTO-CFO composite may be suitable for storage device application.