Investigation on impedance response, magnetic and ferroelectric properties of 0.20(Co1−xZnxFe2−yMnyO4)–0.80(Pb0.70Ca0.30TiO3) magnetoelectric composites

Abstract

In the present work, we report on structural, dielectric, multiferroic, magnetoelectric properties and impedance spectroscopic studies of 0.20(Co1−xZnxFe2−yMnyO4)–0.80(Pb0.70Ca0.30TiO3) (x = 0.4, y = 0; x = 0, y = 0.2 and x = 0.4, y = 0.2) composites. The composites were prepared by metallo-organic decomposition (MOD) route. The coexistence of a cubic spinel phase and a tetragonal phase in the composites is confirmed by the X-ray diffraction measurement. Scanning electron micrographs show well distributed ferrite and ferroelectric phases in the composites. The dielectric properties of the composites have been studied in a wide range of frequency at different temperatures. The temperature dependent dielectric properties of the composites reveal that the ferroelectric–paraelectric transition temperature lies in the range of 499–546 °C. The impedance spectroscopic measurements of the composites indicate non-Debye type dielectric relaxation. The grain and grain boundary contributions in the composites have been separated using impedance spectroscopy analysis. The magnetization hysteresis (M−H) loop of the composites shows ferrimagnetic behavior with saturation magnetization values Ms ∼12–13.4 emu/g and coercive field Hc ∼71–273.5 Oe. The Curie temperature of the composites as determined from the inverse susceptibility vs. temperature curves is in the range of 297–480 °C. All the composites exhibit typical ferroelectric hysteresis loops indicating the presence of spontaneous polarization. A maximum value of magnetoelectric coupling co-efficient α ∼17.4 mV/cm Oe has been observed for the composite with x = 0.4 and y = 0.