Effect of Nd substitution on physical properties of multiferroic compound BiFeO3

Multiferroic materials have attracted great attention due to their potential applications in multifunctional devices. In this work, powders of Bi1−xNdxFeO3 (BNFO) with x = 0.00, 0.05, 0.15 and 0.20 were successfully synthesized by a sol–gel method using bismuth nitrate, iron nitrate and neodymium nitrate as sources. The BNFO powders were annealed at 500 °C. X-ray diffraction patterns revealed the formation of single phases BiFeO3 and BNFO. We observed that the neodymium substitution leads to the change of the BiFeO3 crystal structure from rhombohedral with space group R3c (α-phase) to pseudo-cubic symmetry Pm3 m. A high temperature variety (γ-phase) of multiferroic BiFeO3 compound has been stabilized for 15 % of neodymium content. The morphology of the particles seemed to be approximately spherical, the particle size of the BNFO is between 23 and 67 nm. Those powders show both magnetic transition at Neel temperature (TN) and ferroelectric transition around Curie temperature (TC). In addition a clear ferromagnetic component is observed for all powders. The variations of dielectric constant and dielectric loss, proves a possible coupling between the electric and magnetic dipole in these systems.