Structural and magnetic properties of Er-doped BiFeO₃ nanoparticles

In this work, Bi_1-x Er _x FeO₃ (x = 0.05-0.25) nanoparticles were prepared by sol-gel method. X-ray diffraction and Raman analysis show that the structure of Er-doped BiFeO₃ changes from rhombohedral lattice to orthorhombic one by increasing x. The remnant magnetization of the Bi_1-x Er _x FeO₃ is significantly higher than those in BiFeO₃ doped with non-magnetically rare-earth and it increases with increasing Er concentration. The enhanced magnetization was attributed to the suppression of the cycloidal spin structure by Er³⁺ substitution and the ferromagnetic interaction between Fe³⁺ and Er³⁺ ions. The variation of the magnetization with temperature is also discussed.