摘要
At 105 K, strontium titanate is known to undergo an antiferrodistortive transition transform-ing from cubic to tetragonal structure as a result of the rotation of the oxygen octahedral around a cubic axe. Based on the Curie principle, the order parameter is determined to be a third-order complete symmetry polarization tensor. To take into account of quantum effects,the dielectric permittivity is measured from Landau free energy, and the Curie Weiss-type behavior is analyzed. From crystallization chemistry viewpoint, the dielectric behavior at low temperature is connected to small radius of Sr^2＋, which is much easier to move around the oxygen octahedral than Ba^2＋ in BaTiO3 or Pb^2＋ in PbTiO3.
