Magnetic properties and dielectric behavior in ferrite/ferroelectric particulate composites

Particulate composites of ferrite and ferroelectric phases having the genera I formula (x)BaTiO3+(1-x)Ni0.92Co0.03Cu0.05Fe2O4 (where x is mole fraction of components that varies as 0.85, 0.70 and 0.55) were prepared by conventional double-sintering ceramic method. The presence of constituent phases was confirmed by X-ray diffraction (XRD) technique. The average grain size was determined by using scanning electron micrographs. The variation of dielectric constant and tan 6 with frequency in the range 20 Hz-1 MHz was studied. The variation of loss tangent (tan)) and dielectric constant with temperature at fixed frequencies of 1 kHz, 10 kHz, 100 kHz and 1 MHz was also studied. The saturation magnetization (M-s) and magnetic moment (eta(B) in Bohr magnetons) are reported for all composites. The static magnetoelectric (ME) voltage coefficient was measured as a function of intensity of applied DC magnetic field. The changes were observed in dielectric properties as well as in ME output with variation in molar fraction of constituent phases. A maximum ME conversion factor of 538.59 mu V/cm G was observed for the composites with 70% BaTiO3 + 30% Ni0.92Co0.03Cu0.05Fe2O4. The present ME composites may be useful in preparing devices Such as magnetic sensors and cables, etc. (c) 2007 Elsevier B.V. All rights reserved.