Magnetoelectric properties of PbZr0.53Ti0.47O3–Ni0.65Zn0.35Fe2O4 multiferroic nanocomposites

Abstract

A different kind of multiferroics with ferroelectric–ferrimagnetic (FE–FM) composites: (1 − x) PbZr0.53Ti0.47O3–x Ni0.65Zn0.35Fe2O4 with x = 0.10, 0.20 and 0.30, were synthesized by a powder-in-sol precursor hybrid processing route. Structural analysis with X-ray diffraction (XRD) data revealed the presence of both PbZr0.53Ti0.47O3 (PZT) and Ni0.65Zn0.35Fe2O4 (NZFO) pure phases in the PZT–NZFO composites. Scanning electron micrographs (SEM) clearly disclose distribution of both PZT and NZFO phases throughout the sample. Dielectric and electrical properties of the system have been investigated in a wide range of frequency at different temperatures. Dielectric constant (er) as a function of temperature reveals the paraelectric–FE transition temperature at ~408 °C having maximum value of er at the peak [e r max = 1,200] with another low temperature anomaly at ~297 °C, very close to the magnetic Curie temperature of the NZFO ferrite (Tc = 300 °C) for the x = 0.1 FE–FM composite. The impedance spectroscopy data of these composites show clearly, contribution of both grain and grain boundary effect in the electrical properties of the composites. Negative temperature coefficient of resistance (NTCR) behavior of the materials indicates their semi-conducting nature. The ac conductivity spectrum is found to obey Johnscher’s power law very well. The temperature-dependent magnetization hysteresis (M–H) loops of the PZT/NZFO composite show excellent non-saturating ferrimagnetic behavior with increase in both coercive field (Hc) and remanent magnetization (Mr) when the NZFO content in the composite is increased. Polarization (P) versus electric field (E) studies at 300 K give conclusive evidence of the presence of spontaneous polarization in all the three composites (x = 0.1, 0.2 and 0.3). However, area of P–E loop, coercive field (Ec) and remanent polarization (Pr) are found to decrease noticeably with the increase of the NZFO content (x) in these composites.