Variation of lattice parameter, average grain size, dielectric constant and saturation magnetization with different temperature for 0.30Ni0.7Zn0.3Fe2O4+ 0.70 PLZT composite by Co-precipitation method

Abstract

Magnetoelectric composites containing Ni0.7Zn0.3Fe2O4 and Pb0.93La0.07(Zr0.60Ti0.40)O3 phases have been prepared by chemical co-precipitation method. The structure and morphology of the composites were examined by means of X-ray diffraction (XRD) and scanning electron microscopic (SEM) The XRD result showed that the composites consisted of spinel Ni0.7Zn0.3Fe2O4 and perovskite PLZT annealing at temperature higher than 700 C. The average grain size for the piezoelectric phase of the composite was found to increase the overall dielectric and ferroelectric properties of the composite increased with increasing in sintering temperature. Variation of dielectric constant (ε) and dielectric loss (tanδ) with frequency for 0.30NZFO + 0.70PLZT composite with annealed at different temperature showed dispersion in the low frequency range. The variation of dielectric constant with temperature reflects DPT type behaviour. The dielectric properties are strongly influenced by interface phenomena (Maxwell-Wagner) due to the local electrical inhomgeneity. At low frequency range, the composite showed the dielectric dispersion is associated with very high polarization. The peak value of dielectric constant for composite decreased with increasing its sintering temperature. coercivity, saturation magnetization and squareeness have been found to vary with concentration of ferrite phase and annealing temperature due to the increase in crystallite size. The maximum value of the magnetoelectric conversion factor (dE/dH)max equal to 5.2 mV/cm.Oe is observed for 30%NZFO – 70% PLZT composites when sintered at 1100 C.