Multiferroic materials Bi1-xSmxFeO3: A study of Raman and absorption spectroscopies

Abstract

Multiferroic Bi1-xSmxFeO3 (x = 0.00, 0.05, 0.1, 0.15, 0.2) ceramics were prepared by conventional solid state reaction method. X-ray diffraction measurement was carried out to characterize the crystal structure and to detect the impurities existing in these ceramics. The substitution of rare earth Sm for Bi was found to decrease the impurity phase in BiFeO3 ceramics. There is strong evidence that both lattice constants a and c of the unit cell become smaller as the Sm3+ content is increased. The effect of introducing Sm3+ is shown to decrease the optical band gap for doped sample Bi1-xSmxFeO 3. Additionally, the temperature-dependent Raman measurement performed for the lattice dynamics study of Bi1-xSm xFeO3 samples reveals a strong band centered at around 1000-1300 cm-1 which is associated with the resonant enhancement of two-phonon Raman scattering in the multiferroic Bi1-xSm xFeO3 samples. This two-phonon signal is shown to broaden with increasing x. The Raman spectra at low wavenumbers are suggested to be related with magnon in this system. © 2010 World Scientific Publishing Company.