Dielectric dispersion in BaTiO3 single crystal at low temperatures

The dielectric constants of BaTiO3 single crystals grown by a flux method and a top seeded solution growth (TSSG) method have been reexamined in a wide temperature range of 15 K - 450 K and in a frequency range of 30 Hz - 1 MHz. A low frequency dielectric dispersion with an intensity of Delta epsilon'approximate to 1500 appears at around 100 K only on the crystals grown by the TSSG method. Results of an electric field cooling treatment on the (100)(c) or (111)(c) plates indicate that the dispersion is not due to usual domain-wall motions.