The behavior of the polarization switching by applying electric fields ($E$) along the $\langle 100\rangle$ and $\langle 111\rangle$ directions has been investigated for the single crystals of ferroelectric (${\mathrm{Bi}}_{0.5}$${\mathrm{Na}}_{0.5}$)${\mathrm{TiO}}_3$ (BNT) using high-energy synchrotron radiation x-ray diffraction (SR-XRD) and density functional theory (DFT) calculations. Single-crystal SR-XRD analyses reveal that the $E$-induced switching of spontaneous polarization ($P_{\mathrm{s}}$) occurs via the non-180° (71° and/or 109°) $P_{\mathrm{s}}$ rotation. The DFT calculations show that the energy barrier for the 71° $P_{\mathrm{s}}$ rotation is much lower than those for the 109° $P_{\mathrm{s}}$ rotation and for the direct 180° $P_{\mathrm{s}}$ reversal. These experimental and DFT calculation results lead to the conclusion that the 71° $P_{\mathrm{s}}$ rotation is the dominant pathway for the $E$-induced polarization switching in the BNT crystals.

• Received 8 January 2014
• Revised 24 January 2014

DOI:https://doi.org/10.1103/PhysRevB.89.104104