Enhanced Magnetic and Dielectric Properties in Low-Content Tb-Doped BiFeO₃ Nanoparticles

Bi_1-xTb_xFeO₃ (x=0, 0.01, 0.03 and 0.05) nanoparticles are synthesized by the sol-gel method. A single phase perovskite rhombohedral structure of all the samples is established from the Rietveld refined XRD patterns. The substitution of Tb³⁺ ions to Bi³⁺ decreases the particle size and enhances the ferromagnetic properties of this system. Interestingly a large maximum magnetization value of 1.73 emu/g at 50 kOe can be observed in 1% Tb-doped sample at 300 K. The decrease in band gap may result from the reduced particle size, while the leakage current density also decreases, which is mainly explained by the variation of oxygen vacancies.