Study of monoclinic-tetragonal-cubic phase transition in Pb(Zn1/3Nb2/3)O3-0.08PbTiO3 single crystals by micro-Raman spectroscopy

The relaxor ferroelectric Pb(Zn1/3Nb2/3)O-3-0.08PbTiO(3) (PZN-0.08PT) single crystal has been investigated using polarized micro-Raman scattering technique in a wide temperature range from -150 to 350 degrees C. Raman spectra of the crystal at temperatures lower than 90 degrees C show 11 modes over a frequency range of 100-1000 cm(-1). There are 12 Raman active vibration modes in the monoclinic structure of relaxor ferroelectrics according to the group theory analysis. Thus the structure of PZN-0.08PT single crystal at low temperatures is confirmed as monoclinic. Two structural phase transitions in the crystal were observed when the temperature was increasing. First, the monoclinic-tetragonal (M-T) phase transition happens at 90 degrees C. Second, the tetragonal-cubic (T-C) phase transition takes place at 170 degrees C.