Size-dependent magnetic and dielectric properties of Tb-doped BiFeO3 nanoparticles

Pure and Tb-doped BiFeO3 nanoparticles have been prepared by sol-gel method. The nanoparticles of different size have been obtained by the calcination of synthesized nanoparticles at different temperatures. The effects of Tb doping and size of nanoparticles on the crystal structure, magnetic and electrical properties have been studied. The partial substitution of Tb ions results in a change from rhombohedral (x = 0) to orthorhombic (x = 0.15) structure. The average crystallite size varies from 14 to 40 nm. The synthesized nanoparticles possess ferromagnetic behavior. The saturation magnetization is high for the Tb-doped BiFeO3 nanoparticles calcined at 450 A degrees C, and it decrease with the increase of size. The dielectric constant and loss improve with Tb doping and size. The relaxation behavior of dielectric loss is of Debye type. The dielectric loss peaks shift to the lower frequencies with increase in the size of Tb-doped BiFeO3 nanoparticles.