Magnetic properties and dielectric behavior in ferrite/ferroelectric particulate composites

Abstract

Particulate composites of ferrite and ferroelectric phases having the general formula ( x)BaTiO 3+(1– x)Ni 0.92Co 0.03Cu 0.05Fe 2O 4 (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 δ with frequency in the range 20 Hz–1 MHz was studied. The variation of loss tangent (tan δ) 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 ( η 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 μV/cm G was observed for the composites with 70% BaTiO 3+30% Ni 0.92Co 0.03Cu 0.05Fe 2O 4. The present ME composites may be useful in preparing devices such as magnetic sensors and cables, etc.