The Effect of Ba Doping on the Structural, Optical, Magnetic, and Dielectric Properties of BiFeO3 Nanoparticles

Nanoparticles (Nps) of Ba (0, 1 to 5 at.%)-doped BiFeO3 were synthesized by a sol-gel route at 100 °C using tartaric acid as a chelating agent. The obtained results were studied by using XRD, SEM with EDAX, TEM, UV-vis diffusion reflectance spectra, VSM, and impedance analyzer. EDAX spectra confirmed the presence of Bi, Ba, and Fe in the samples. X-ray diffraction studies showed that BiFeO3 and Bi1−xBaxFeO3 samples exhibited the expected rhombohedral perovskite structure up to a Ba concentration of 3%, whereas 4 and 5% of Ba concentration exhibited the tetragonal phase. TEM studies indicate the particle sizes in the range of 08–28 nm. Reflectance spectra measurements showed a decrease in band gap with increasing Ba concentration. Magnetic properties indicated that the undoped BiFeO3 and Ba-doped BiFeO3 samples were ferromagnetic at room temperature. The dielectric constant (ε′) and loss (ε″) show large dispersion behavior. The dielectric constant increases with an increase of dopant concentration, but a very high value of the dielectric constant was noticed for x = 0.05.