Multiferroic behavior of nanocrystalline BaTiO3 sintered at different temperatures

BaTiO3 (BTO) nanoparticles were prepared via the sol–gel method by sintering at different temperatures (600–1000 °C). X-ray diffraction (XRD) patterns confirm the pure phase formation of BTO for all samples. Transmission Electron Microscopy (TEM) images show that the particle size of BTO samples varies from 20 to 43 nm for the samples sintered from 600 to 1000 °C, respectively. The optical band gap decreases from 4.21 to 3.38 eV by increasing sintering temperature, respectively. Polarization versus Electric field (P–E) loops of BTO samples sintered from 600 to 800 °C indicate the loosy capacitor behavior which tends towards non-linear ferroelectric behavior for sample sintered at 900 and 1000 °C. Dielectric constant and dielectric loss increase as the sintering temperature increases from 600 to 1000 °C. Furthermore, room temperature magnetization versus magnetic field (M–H) loops show a weak ferromagnetic behavior for the sample sintered at 600 °C whereas mixed ferromagnetic and diamagnetic phase is observed for the sample fired at 1000 °C. The observation of both ferroelectricity and ferromagnetism in nanocrystalline BaTiO3 is interesting and make it as a possible single phase multiferroic material.