Electric and Magnetic Properties of the (1 -x)Bao.6Sr0.4TiO3-xCoFe2O4 Multiferroic Composite Ceramics

The(1-x)Bao.6Sro.4 TiO3-xCoFe2O4 multiferroic composite ceramics (x=0.15-0.45) were fabricated by using the solid-state reaction method.X-ray diffraction shows that the composites are composed of the perovskite Ba0.6Sr0.4TiO3 phase and cubic spinel CoFe2O4 phase,without the other secondary phase.Scanning electron microscopy shows that the morphology of the composites is dense and comparatively homogenous.The variations of the dielectric constant and loss with frequency and temperature indicate that the composites behave as relaxor ferroelectrics.The composites display ferromagnetic and ferroelectric properties simultaneously.The saturated polarization of the composites decreases with increasing ferrite content,while the remnant polarization increases with the increasing ferrite content.The remnant polarization of the composite with x =0.45 is even larger than that of the pure Ba0.6Sr0.4TiO3 ceramic.The enhanced ferroelectricity of the composites may be attributed to the space charge effect in the composites.