Effect of Particle Size on Magnetic and Dielectric Properties of Nanoscale Dy-Doped BiFeO3

In the present report, influence of Dy-substitution and size on the structural, magnetic and dielectric properties of BiFeO3 nanoparticles has been investigated. The synthesis of pure and Dy-doped BiFeO3 nanoparticles has been done successfully using sol-gel method. Size of Dy-doped BiFeO3 nanoparticles was tailored by varying the calcination temperature. Structural analysis reveal that substitution of Dy3+ leads to a change in structure from rhombohedral (x=0) to orthorhombic (x=0.15). The average crystallite size varies from 6 to 15 nm. Magnetic study reveals the enhancement in magnetization with the doping of Dy3+. Further, this value decreases as the particle size increases. Dielectric property improves with the Dy3+ substitution. All the nanoparticles display Debye-type relaxation. The low dielectric loss values observed are attributed to the nanosized grains. Remarkably, enhanced saturation magnetization value (13.8 emu/g) and dielectric constant value (95.8) were observed for Dy-doped BiFeO3 nanoparticles having the smallest particle size. Thereby, the study indicates strong correlation between size and multiferroism.