Ferroelectric mesocrystalline BaTiO3/BaBi4Ti4O15 nanocomposite: formation mechanism, nanostructure, and anomalous ferroelectric response

Ferroelectric mesocrystalline nanocomposites are promising materials for the enhancement of ferroelectricity via lattice strain engineering due to their high density of heteroepitaxial interfaces. In the present study, a ferroelectric mesocrystalline BaTiO3/BaBi4Ti4O15 (BT/BBT) nanocomposite was synthesized using the layered titanate H1.07Ti1.73O4 via a facile two- steptopochemical process. The BT/BBT nanocomposite is constructed from well- aligned BT and BBT nanocrystals oriented along the [110] and [11- 1] crystal- axis directions, respectively. Lattice strain is introduced into the nanocomposite through the formation of a BT/BBT heteroepitaxial interface, which results in a greatly elevated Curie temperature for BBT in the range of 400 degrees C to 700 degrees C and an improved piezoelectric response with d*(33) = 130pmV(-1). In addition, the BT/BBT nanocomposite is stable upto a high temperature of 1100 degrees C; therefore, mesocrystalline ceramics can be fabricated as high- performance ferroelectric materials.