Ferroelectric BaTiO3 nanoceramics prepared by a three-step high-pressure sintering method

Dense BaTiO3 nanoceramics with a homogeneous grain size of 30 nm were prepared at 6 GPa, 1000 degrees 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 BaTiO3 ceramics, successive phase transitions are observed in the 30 nm BaTiO3 ceramics using variable-temperature X-ray diffraction measurements. Furthermore the 30 mn BaTiO3 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 degrees C lower than that of a normal bulk sample. The results indicate that dense 30 nm BaTiO3 ceramics retain ferroelectricity above room temperature. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.