Strontium Titanate (SrTiO3)

Abstract

Strontium titanate (SrTi03) crystallizes in the cubic perovskite structure. Optical properties are therefore isotropic. Strontium titanate generally behaves like a ferroelectric material in the paraelectric phase. This property is commonly referred to as “incipient ferroelectric.” It is noted that the hypothetical Curie temperature takes place just below the absolute-zero temperature. As a result, the dielectric constant is strongly dependent on temperature and increases by a factor as large as 10 when the sample is cooled from the room temperature to liquid helium temperature. Because the dielectric constant is the extrapolation down to zero frequency of the dielectric response, thus optical constants also vary with temperature, but mainly in the far infrared. In addition, a phase transition related to the alternate tilt of oxygen octahedra, which results in the formation of a tetragonal structure, takes place upon cooling below 105 K . The temperature dependence of data related to optical constants is essentially studied in various references for the ultraviolet range, in the visible and in the infrared.