Room-Temperature Multiferroic Properties and Local Structures of the Mn-Doped and (Pb, Mn)-Codoped BiFeO3

The Mn-doped and the (Pb, Mn)-codoped BiFeO₃ polycrystalline samples are prepared by a sol–gel method. The X-ray diffraction patterns manifest that all samples are in single phase and a lattice structural transformation appears during doping process. Compared with Mn-doped BiFeO₃, the magnetic property of (Pb, Mn)-codoped BiFeO₃ is enhanced and ferroelectric polarization decreases. The results of XAFS indicate that the bond length of Fe–O shortens due to doping Mn ions into BiFeO₃, which results in the increase of magnetic property. Pb ion doping makes the valence state of Mn ion change, rather than Fe ion, and induces the occurrence of Mn⁴⁺–O–Fe³⁺ antiferromagnetic coupling, which decreases the magnetic property of the Bi_0.95Pb_0.05Fe_0.95Mn_0.05O₃ sample.