Domain Wall Architecture in Tetragonal Ferroelectric Thin Films.

Non-Ising-like 180° ferroelectric domain wall architecture and domain distribution in tetragonal PbZrx Ti1- x O3 thin films are probed using a combination of optical second harmonic generation and scanning transmission electron microscopy. In the remnant state, a specific nonlinear optical signature of tilted 180° domain walls corresponding to a mixed Ising-Néel-type rotation of polarization across the wall is shown.