Fabrication of BaTiO₃/BiFeO₃ Nano-complex Ceramics by Hydrothermal Method

抄録

To enhance the dielectric properties of barium titanate (BaTiO₃, BT)/bismuth ferrite (BiFeO₃, BF) nano-complex ceramics by a polarization rotation mechanism like a lead zirconate titanate, we tried to introduce structure-gradient region (SGR) in the BT/BF nano-complexes by constructing epitaxial interface between BT and BF layers. The green compacts consisting of TiO₂ and BF nano-particles were hydrothermally converted into the BT/BF complexes compacts with various BT/BF molar ratios. It can be observed that the epitaxial BT layers were formed on the BF particles in the BT/BF complex with a molar ratio BT/BF=0.50 by the high-resolution transmission electron microscope. The dielectric properties of these nano-complexes tend to increase monotonically with the BT/BF molar ratio and the remarkable enhancement cannot be found despite of the formation of the BT/BF epitaxial interface. It can be considered that the displacement of Ti ions might be limited by the compressive stress on BT lattices due to the lattice mismatch at the epitaxial interface, and the dielectric properties did not enhance even if the SGR formed.