Research of Structure Ordering in Ceramic Ferroelectromagnets Bi 1 x La x FeO 3 by Raman Spectroscopy
The ordering processes in structures of ceramic ferroelectromagnets Bi1 x La x FeO3 (x 0.075 0.20) is researched by Raman spectra It was discovered that Bi1 x La x FeO3 structure is close to the one of BiFeO3 However, bands in Raman spectra of Bi1 x La x FeO3 were much wider than bands of single crystal BiFeO3 which means that in ceramics solid solutions structure is more disordered than in single crystals. In Raman spectra of Bi1 x La x FeO3 in the area of oxygen octahedrons librations (50 90 cm 1) several groups of bands with frequencies 59 69, 72 77, 86 92 cm 1 were observed in dependence of solid solution compound. This result confirms XRD data that researched solid solutions are not single phase. At La (x 0.120) low frequency bands in Raman spectra narrowed which indicates ordering of structure units in cation sublattices. At increase of La concentration in Bi1 x La x FeO3 structure, unambiguous dependence of spectral bands parameters was not observed. Perhaps this could be explained by the fact that at increase of x value, character of La integration to the solid solution structure changes.