Effect of the Annealing Conditions on the Strain Responses of Lead-Free (Bi0.5Na0.5)TiO3-BaZrO3 Ferroelectric Thin Films

Bismuth sodium titanate (Bi0.5Na0.5)TiO3 (BNT)-based thin films have attracted large attention for the production of modern precise micro-devices due to their outstanding strain responses. However, obtaining good electrical properties and low leakage current in BNT-based thin films is still a great challenge. In this work, 0.945(Bi0.5Na0.5)TiO3-0.055BaZrO(3) (BNT-5.5BZ) thin films were deposited by the chemical solution deposition (CSD) method and annealed under two different conditions. This work describes a careful research study on the influence of the annealing conditions on the crystalline structure, morphology, and electrical performance of the BNT-5.5BZ thin films. The films exhibited a dense structure and excellent electrical properties following an optimized thermal treatment process. An ultra-high strain response of 1.5% with a low dielectric loss of similar to 0.03 was obtained in the BNT-5.5BZ thin films after post-annealing in an O-2 atmosphere. The results of this work show that the enhanced strain response was mainly due to a reversible field-induced phase transition between the ferroelectric phase and the relaxation state. The post-annealing treatment is an effective method to optimize the electrical properties of BNT-based films, providing many opportunities for the application of ferroelectric devices.