Ferroelectric BaTiO 3 nanoceramics prepared by a three‐step high‐pressure sintering method

Dense BaTiO 3 nanoceramics with a homogeneous grain size of 30 nm were prepared at 6 GPa, 1000 °C using a three‐step high‐pressure sintering method. The microstructure of the ceramics obtained is uniform and the relative density is above 98% of the theoretical value. Similar to normal BaTiO 3 ceramics, successive phase transitions are observed in the 30 nm BaTiO 3 ceramics using variable‐temperature X‐ray diffraction measurements. Furthermore the 30 nm BaTiO 3 ceramics reveal ferroelectric properties after being post‐annealed at low temperature in O 2 atmosphere, but the phase transition temperature from paraelectric to ferroelectric phase is 10 °C lower than that of a normal bulk sample. The results indicate that dense 30 nm BaTiO 3 ceramics retain ferroelectricity above room temperature. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)