Observation of enhanced room temperature multiferroicity in nanoparticles BiFeO₃

Impurity free monophasic rhombohedral BiFeO₃ (BFO) nanoparticles are synthesized by sol–gel method. Effect of processing technique and particle size are found to influence the dielectric, ferroelectric, magnetic and leakage behavior of BFO ceramic prepared by sol–gel as well as conventional solid state reaction route. From XRD analysis it is observed that bulk BFO sample showed rhombohedral structure (R3c) along with other impurity phases, which become suppressed with the decrease of particles size to few nanometers. The dielectric behavior and leakage current characteristic of the samples were improved significantly in nanoparticles of BFO. Ferroelectric hysteresis loops of sintered bulk BFO ceramic is found to change its shape from semi elliptical lossy P–E features to a typical ferroelectric feature with improved remnant and saturation polarization value for the particle size down to nanometer scale. Furthermore, BFO nanoparticles also showed a good ferromagnetic M–H hysteresis loop with enhanced saturation magnetization value of 0.138 emu/mg.