Temperature dependence of BaTiO_3 infrared dielectric properties

摘要

The infrared dielectric constants of the perovskite BaTiO_3 are obtained by infrared spectroscopic ellipsometry in the temperature range of 20-150℃. Apparent temperature-dependent distribution of the spectral weight xariation is observed for complex dielectric function. Both high frequency dielectric function and bound electrical charge show the temperature dependence from the tetragonal to the cubic phase transition. The bound electrical charge appears to be composed of a hopping component and a temperature-dependent one for BaTiO_3 with first-order transitions.