Pressure evolution of local structure and vibrational dynamics of the perovskite-type relaxor ferroelectric single crystal of 0.935(Na0.5Bi0.5)TiO3-0.065BaTiO3(NBT-6.5BT)is systematically investigated via in situ Rama...Pressure evolution of local structure and vibrational dynamics of the perovskite-type relaxor ferroelectric single crystal of 0.935(Na0.5Bi0.5)TiO3-0.065BaTiO3(NBT-6.5BT)is systematically investigated via in situ Raman spectroscopy.The pressure dependence of phonon modes up to 30GPa reveals two characteristic pressures:one is at around 4.6GPa which corresponds to the rhombohedral-to-tetragonal phase transition,showing that the pressure strongly suppresses the coupling between the off-centered A-and B-site cations;the other structural transition involving the oxygen octahedral tilt and vibration occurs at pressure∼13–15GPa with certain degree of order-disorder transition,evidenced by the abnormal changes of intensity and FWHM in Raman spectrum.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.11674231,11974250,and 51772192)the Science and Technology Commission of Shanghai Municipality(Grant Nos.17070502700 and 19070502800)the Shenzhen Development and Reform Commission Foundation for Shenzhen Engineering Research Center for Frontier Materials Synthesis at High Pressures.
文摘Pressure evolution of local structure and vibrational dynamics of the perovskite-type relaxor ferroelectric single crystal of 0.935(Na0.5Bi0.5)TiO3-0.065BaTiO3(NBT-6.5BT)is systematically investigated via in situ Raman spectroscopy.The pressure dependence of phonon modes up to 30GPa reveals two characteristic pressures:one is at around 4.6GPa which corresponds to the rhombohedral-to-tetragonal phase transition,showing that the pressure strongly suppresses the coupling between the off-centered A-and B-site cations;the other structural transition involving the oxygen octahedral tilt and vibration occurs at pressure∼13–15GPa with certain degree of order-disorder transition,evidenced by the abnormal changes of intensity and FWHM in Raman spectrum.
