Giant piezoelectricity in oxide thin films with nanopillar structure
Huajun Liu, Haijun Wu, Khuong P. Ong, Tiannan Yang, Ping Yang, Pranab K. Das, Xiao Chi, Yang Zhang, Caozheng Diao, Wai Kong Alaric Wong, Eh Piew Chew, Yi Fan Chen, Chee Kiang Ivan Tan, Andrivo Rusydi, Mark B. H. Breese, David J. Singh, Long‐Qing Chen, Stephen J. Pennycook, Kui Yao
Abstract
High-performance piezoelectric materials are critical components for electromechanical sensors and actuators. For more than 60 years, the main strategy for obtaining large piezoelectric response has been to construct multiphase boundaries, where nanoscale domains with local structural and polar heterogeneity are formed, by tuning complex chemical compositions. We used a different strategy to emulate such local heterogeneity by forming nanopillar regions in perovskite oxide thin films. We obtained a giant effective piezoelectric coefficient [Formula: see text] of ~1098 picometers per volt with a high Curie temperature of ~450°C. Our lead-free composition of sodium-deficient sodium niobate contains only three elements (Na, Nb, and O). The formation of local heterogeneity with nanopillars in the perovskite structure could be the basis for a general approach to designing and optimizing various functional materials.