Structural, electric transport response and electro -strain - Polarization effect in La and Ni modified bismuth ferrite nanostructures

Abstract

In this work, we reported the structural properties, electrical transport response and electro-strain polarization effect of La-Ni bismuth ferrite nanostructures, Bi1-XLaXFe1-YNiYO3 (x = 0.0, 0.1; y = 0.0, 0.03, 0.05, 0.07) prepared via sol gel technique. X-ray diffraction (XRD) analysis confirmed the rhombohedral crystal structure with space group R3c of BiFeO3. The Ni ion doping at a Fe - site in BiFeO3 escorts to some structural changes and the average crystallite size was found to be in range ∼13–20 nm. The higher tensile strain was observed in W-H Plot for the prepared samples. The morphological and chemical composition studies of as prepared samples were carried out via using SEM and EDS. Dielectric constant (έ) and AC conductivity (σAC) were deliberated as a function of frequency in the range 10 Hz to 5 MHz. A significant reduction in the dielectric constant has been observed with increasing Ni doping. An enhancement in the remanent polarization (2Pr) value (up to 1.04 μC/cm2 with applied field 8 kV/cm) and AC conductivity has been observed with La/Ni co-doping. The high Curie temperature (Tc) of BFO makes it a suitable candidate for high temperature electromechanical applications. Moreover, an enhanced value of the electric field driven strain as a function of frequency and the applied field is observed which exhibits highly asymmetric S-E hysteresis loops. The peak to peak strain value of Sp and SN is achieved up to 1.019% and 1.582%, respectively, which is the largest value of strain ever obtained in BiFeO3 based nano ferrites. The highest value of peak to peak strains (SP & SN) and strain memory (Sme) has been observed for Bi0.9La0.1Fe0.93Ni.07O3 sample at 8 kV/cm which makes it a suitable candidate for high temperature electromechanical applications (like sensors and actuators etc) in addition to electronic and magnetic applications.