Improved magnetic and ferroelectric properties of Sc and Ti codoped multiferroic nano BiFeO3 prepared via sonochemical synthesis

Abstract

The room temperature multiferroic properties of bulk BiFeO₃ are not exciting enough for its application in devices. Here, we report the sonochemical synthesis of scandium and titanium codoped BiFeO₃ nanoparticles which exhibit improved magnetic and ferroelectric properties at room temperature. The nanoparticles have been checked for phase purity and composition using powder X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The size and morphology of the nanoparticles have been confirmed using scanning electron microscopy (SEM), and both low and high resolution transmission electron microscopy (TEM/HRTEM). The breaking of the spin cycloid due to the smaller size and slight structural distortion caused by the doping has been found to be instrumental for the enhancement of multiferroic properties. The electrical polarization increases significantly in the case of BiFe_0.925Sc_0.05Ti_0.025O₃ nanoparticles. A marked reduction in the leakage current was seen compared to undoped BiFeO₃. Magnetoelectric coupling was also observed in the BiFe_0.925Sc_0.05Ti_0.025O₃ sample. Our results demonstrate that codoping with Sc and Ti ions is an effective way to rectify and enhance the multiferroic nature of BiFeO₃.