Temperature dependence of the A1 and E optical phonons in BaTiO3

Abstract

Measurements of all A₁ and E transverse and longitudinal phonons in BaTiO₃ are reported in the temperature range 10 to 132 °C where the crystal is in the tetragonal phase. A least squares fitting of the spectral shapes is done and the resulting temperature dependence of the frequencies, linewidths and coupling parameters is presented. The temperature dependence of the phonon and electron contribution to the dielectric constant, ε, in the c‐ and α‐axes is determined and compared to the capacitance measurements. It is found that the dielectric constant discrepancy is highly anisotropic.