Magneto-electric coupling and improved dielectric constant of BaTiO^sub 3^ and Fe-rich (Co^sub 0.7^Fe^sub 2.3^O^sub 4^) 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 He 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, αME = 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.