Fabrication of the Cobalt Ferrite/Modified Sodium Bismuth Titanate 0-3 Multiferroic Composites via Diffusion-blocking

The ZrO2 buffer layer was coated on CoFe2O4(CFO) powder via a Sol-Gel method.The coated CFO and 0.92(Bi0.5Na0.5)TiO3-0.02(Bi0.5K0.5)TiO3-0.06BaTiO3(BNBT) ceramic powder were mixed according to the chemical formula of xCFO/(1-x) BNBT(weight fraction x=0.05,0.10,0.15,0.20,0.25,0.30).Using polyvinyl alcohol(PVA) as binder,the mixture was pressed into disks.After sintered at 1050℃,the xCFO/(1-x) BNBT 0-3 composite ceramic disks were prepared.The X-ray diffraction results show that the ZrO2 layer can buffer the Fe3+ and Co2+ ions diffusing from CFO to BNBT during the sintering process.The break-down voltage of the co-fired composites is measured to be 75kV/cm.It is found that the piezoelectric constant,electromechanical coefficient,remnant polarization and dielectric permittivity decrease as the CFO content increasing.Magnetoelectric coefficient(ME) and dielectric loss increase with the CFO content increasing.For a composite disk with dimension of φ35mm×1.5mm,the ME coefficient at resonance frequency of 90 kHz is 1.39V/A under a DC magnetic bias of 199 kA/m.