Ferroelectric Domain Structures in Monoclinic (K0.5Na0.5)NbO3 Epitaxial Thin Films.

Ferroelectric domain walls (DWs) are an important feature of ferroelectric materials and play a vital role in the ferroelectric materials, where charged DWs are a focus of extensive research due to their unique interfacial properties. Herein, epitaxial (K,Na)NbO3 (KNN)‐based thin films are prepared by a sol–gel method, and the monoclinic MC structure of the thin film is confirmed. Stripe‐shaped domain patterns with head‐to‐head and tail‐to‐tail charged DWs in the (110)pc and (1¯10)pc planes are observed in the KNN‐based epitaxial thin film. Although the screening of the bound charges in the charged DWs inevitably increases the energy of the system, the charged DWs in the KNN‐based epitaxial thin film are stabilized by the lattice mismatch strain between the thin film and the substrate. These interesting findings should shed light on the exploration of the functional charged DWs by strain engineering. [ABSTRACT FROM AUTHOR]