Electrical properties and magnetoelectric effect in(x)Ni0.5Zn0.5Fe2O4+(1−x)BPZT composites

Abstract

Magneto electric (ME) composites with the composition(x)Ni0.5Zn0.5Fe2O4+(1−x)Ba0.8Pb0.2Zr0.8Ti0.2O3 (BPZT—barium lead zirconate titanate), in whichx varies as 0.0, 0.15, 0.30, 0.45, and 1.0 in molar ratio, were prepared by the conventionaldouble sintering ceramic technique. The presence of two phases, namely ferrite (Ni0.5Zn0.5Fe2O4) andferroelectric (Ba0.8Pb0.2Zr0.8Ti0.2O3), was confirmed by x-ray diffraction analysis. The DC resistivity wasmeasured as a function of temperature, and the AC conductivity (σAC) as a function of frequency (100 Hz–1 MHz). From the experimental results, it is concluded thatthe conduction in these composites is due to small polarons. The relative dielectric constantwith variation of frequency (in the range of 20 Hz–1 MHz) and temperature at four fixedfrequencies (i.e. 1 kHz, 10 kHz, 100 kHz, and 1 MHz) was studied. The hysteresis behavior wasstudied to understand the magnetic properties such as saturation magnetization (Ms) and magneticmoment (μB). The static magneto electric voltage coefficient(dE/dH)H was measured as a function of applied DC magnetic field and it increases first andthen decreases with increasing magnetic field. The variation of the ME responsewas explained in terms of the ferrite content, the resistivity of the compositesand the intensity of the magnetic field. The maximum ME conversion factor,698 μV cm−1 Oe−1, was observed forthe composite with 30% ferrite+70% ferroelectric.