Thermal Diffuse Streak in Electron Diffraction and Low Frequency Transverse Optic Lattice Waves of Barium Titanate

Abstract

With the use of selected area electron diffraction technique of electron microscopy, the thermal diffuse scattering due to low frequency transverse optic lattice waves of barium titanate was observed in both tetragonal and cubic phases. In the tetragonal phase there exists strong intensity distribution on (100)_tet and (010)_tet planes in the reciprocal space, but weak one on (001)_tet plane perpendicular to ferroelectric polar-axis. In the cubic phase strong intensity distribution is found on all of {100}_cub planes.