Effect of Nd/Mn substitution on the structure and magnetic properties of nano-BiFeO3

The structure and magnetic property of pure and Nd/Mn doped nano-BiFeO3, prepared by the conventional hydrothermal method, were investigated at room temperature using X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) spectroscopy, and superconducting quantum interference device (SQUID). The XRD results showed that all samples had rhombohedral R3c crystal structure and no impurity phases were observed, and further confirmed by our Bi L3-edge and Fe K-edge XAFS spectra. Surprisingly, our Nd L3-edge XAFS results revealed clearly that Nd-doping induced a nanoscale phase transition from R3c crystal structure to Pnma, and then promoted the formation of the nanoscale phase-separated particles. In contrast, the Mn doped nano-BiFeO3 remained R3c crystal structure. We also discussed the influence of Nd and Mn doping in two sites on the magnetic properties of nano-BiFeO3.