Ferroelectric polarization and domain walls in orthorhombic (K1-xNax)NbO3 lead-free ferroelectric ceramics

Combining aberration-corrected high-resolution transmission electron microscopy with first-principles calculations, we have investigated the ferroelectric polarization and the atomic structures of 60 degrees/120 degrees domain walls in orthorhombic (K0.46Na0.54)NbO3 lead-free ferroelectric ceramics. The projections of cation-oxygen dipoles across the 60 degrees/120 degrees domain walls were determined using the recently developed negative spherical-aberration imaging technique. The measured ferroelectric distortion matched well with that obtained from first-principles calculations. The width across the wall was measured to be similar to 1.1 nm. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3442905]