Tetragonal Distortion of a BaTiO(3)/Bi(0.5)Na(0.5)TiO(3) Nanocomposite Responsible for Anomalous Piezoelectric and Ferroelectric Behaviors

[Image: see text] Ferroelectric mesocrystalline nanocomposites are functional materials with improved ferroelectricity via lattice strain engineering. In this study, X-ray diffraction (XRD) and soft X-ray absorption spectroscopy (XAS) are performed to determine the tetragonal distortion of Bi(0.5)Na(0.5)TiO(3) (BNT) in a ferroelectric mesocrystalline BaTiO(3) (BT)/BNT nanocomposite. The XRD results demonstrate the expansion of the BNT lattice in the BT/BNT nanocomposite. Using Williamson–Hall analysis, the tensile strain of BNT in BT/BNT-700 is confirmed. Shift and splitting of the e(g) orbital are observed for BNT in the BT/BNT nanocomposite in Ti L(3)-edge XAS, suggesting the lower symmetry of the TiO(6) octahedron in BNT, which is ascribed to a significant tetragonal distortion of BNT in the BT/BNT nanocomposite caused by the lattice mismatch between BNT and BT. It is found that the tetragonally distorted BNT in BT/BNT is responsible for the anomalous ferroelectric response of the mesocrystalline BT/BNT nanocomposite.