Thermal Conductivity of SrTiO₃, KTaO₃ and BaTiO₃ near the Curie Points

Abstract

The thermal conductivity λ near the Curie points of SrTiO 3 , KTaO 3 and BaTiO 3 is studied theoretically. The following results are obtained. (1) In SrTiO 3 λ decreases gradually in the high temperature region (about T -0.5 ) and has a sharp decrease in the lower temperature side of the Curie point (32 K). (2) In KTaO 3 λ decreases as T -1 in the high temperature side of T max ∼30 K, whereas it decreases sharply in low temperatures, T max being the temperature of maximum λ. (3) For BaTiO 3 a dip near the Curie point (391 K) in the λ– T curve is derived. These features are in accord with recent experiments.