Raman and dielectric spectroscopy in the disordered Pb(Sc 1/2 Nb 1/2 )O 3 relaxor fabricated by using a one-step mixed oxide method

Complex perovskite Pb(Sc 1/2 Nb 1/2 )O 3 ceramics were prepared under three different conditions by using the conventional mixed oxide method. Sintering under different conditions resulted in complete formation of the perovskite phase in all of the samples. The microstructure of Pb(Sc 1/2 Nb 1/2 )O 3 was observed by using field-emission scanning electron microscopy (FE-SEM). Raman spectra and the dielectric constant as functions of the temperature were measured. Raman spectra showed a shift to lower frequencies of the F 2 g O-B-O symmetrical bending mode and changes in the intensities and the line widths of the dirty modes with increasing sintering temperature. Also, at low wavenumbers (180 to 400 cm −1 ), significant changes were observed due to increasing structural distortion with increasing sintering temperature. At approximately the Cure temperature (T c ), a phase transition of the sintered Pb(Sc 1/2 Nb 1/2 )O 3 samples occurred over a broad range of temperatures.