Tunable physical properties of Ba doped BiFeO3 multiferroic nanoceramics for capacitor and memory storage devices

Abstract

Recently, perovskite structured bismuth ferrite (BiFeO3) multiferroic material has been widely studied owing to its potential applications in various devices like spintronics, energy storage, sensors and photovoltaic devices. Interestingly, the presence of two or greater stable polarization states in this material and the ease of polarization switching by way of electric field exhibited high energy storage densities, making it appropriate for information storage devices. However, the large leakage current and weak magnetism associated with the material at 300 K hinders its usage in practical applications. It is noticed that the substitution of Bi by alkaline earth elements (Mg2+, Sr2+, Ca2+) could significantly enhance the physical properties of BiFeO3 ceramics. In this work, Bi1-xBaxFeO3 (x = 0.05–0.2 mol %) nanoceramics were prepared by adopting low temperature molten salt synthesis route using NaCl as flux. The X-ray diffraction studies revealed the formation of distorted perovskite structure of BiFeO3 phase in all the range of compositions studied. The FESEM analysis demonstrated the presence of nanosized grains of BiFeO3 and the average grain size decreases with an increase in Ba doping content. The X-ray photoelectron spectra revealed the existence of different valence states of the elements present in BiFeO3 nanoceramics. It is interesting to observe that the dielectric properties of Ba doped BiFeO3 ceramics are superior to the undoped samples, especially at the higher frequency range due to the ionic size difference of barium and bismuth ions in the crystal lattice of BiFeO3, which would significantly influence the energy storage capacity in the non-volatile random access memory storage devices.