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

Magneto electric (ME) composites with the composition (x)Ni0.5Zn0.5Fe2O4 + (1 - x)Ba0.8Pb0.2Zr0.8Ti0.2O3 (BPZT-barium lead zirconate titanate), in which x varies as 0.0, 0.15, 0.30, 0.45, and 1.0 in molar ratio, were prepared by the conventional double sintering ceramic technique. The presence of two phases, namely ferrite (Ni0.5Zn0.5Fe2O4) and ferroelectric ( Ba0.8Pb0.2Zr0.8Ti0.2O3), was confirmed by x-ray diffraction analysis. The DC resistivity was measured as a function of temperature, and the AC conductivity (sigma(AC)) as a function of frequency (100 Hz-1 MHz). From the experimental results, it is concluded that the conduction in these composites is due to small polarons. The relative dielectric constant with variation of frequency (in the range of 20 Hz - 1 MHz) and temperature at four fixed frequencies (i.e. 1 kHz, 10 kHz, 100 kHz, and 1 MHz) was studied. The hysteresis behavior was studied to understand the magnetic properties such as saturation magnetization (M-s) and magnetic moment (mu(B)). The static magneto electric voltage coefficient (dE/dH)(H) was measured as a function of applied DC magnetic field and it increases first and then decreases with increasing magnetic field. The variation of the ME response was explained in terms of the ferrite content, the resistivity of the composites and the intensity of the magnetic field. The maximum ME conversion factor, 698 mu V cm(-1) Oe(-1), was observed for the composite with 30% ferrite + 70% ferroelectric.