SOME PHYSICAL PROPERTIES OFBaTiO3–CoFe2O4COMPOSITE

Abstract

[X]% BaTiO3[100-x]% CoFe2O4composites (x = 0, 20, 40, 60, 80, and 100) were prepared by the general ceramic method. X-ray diffraction patterns and IR spectra confirmed the presence of two phases beside identified phase in the composites with (x% = 40-80% BaTiO3).The temperature variation of conductivity was mainly attributed to change of the drift mobility rather than to the variation of charge carrier concentration. All the composites showed p-type behaviors in the range of temperature 300–400 K. For T > 400 K all composites showed n-type behavior. At this high temperature, the conduction is mainly due to Fe3+→ Fe2+. Hence, there is a p–n transition.The variation of dielectric constant as a function of temperature showed a peak value at the Curie temperature (around 390 K) of ferroelectric phase in composites. It is also noted that the phase transition temperature Tcvaried for different composites.The relation between charge carrier mobility log (μd) versus (1/T) is nearly linear supporting the polaron hopping model for the conduction. The activation energies calculated from resistivity and that from mobility are in close agreement indicating localized model of charge carrier.The initial permeability increased with increasing temperature which is due to the activation of hopping electrons between Fe3+and Fe2+giving rise to the magnetic moment of the composites.