Decoding the Role of Diffused Multiphase Coexistence in Potassium Sodium Niobate-Based Ceramics with Nanodomains for Enhanced Piezoelectric Devices

Abstract

Although multiphase coexistence endows potassium sodium niobate (KNN)-based ceramics with enhanced piezoelectric properties and promising potential in electronic devices, the physical mechanisms are still left way far behind. In this paper, (1-x)K0.48Na0.52Nb0.95Sb0.05O3-x(Bi0.5Ag0.5)(Zr0.9Hf0.1)O3 ceramics were selected as an example to probe the physical mechanisms. By tailoring the x value, a diffused rhombohedral-orthorhombic-tetragonal (R-O-T) coexistence was obtained at x = 0.04, affording a large piezoelectric coefficient d33 of 510 pC/N and a high Curie temperature Tc of 219 °C. The piezoelectricity enhancement mainly originated from the enhanced dielectric response and abundant submicron striped domains (50-100 nm) consisting of hierarchic nanodomains (10-15 nm). Importantly, although the diffused R-O-T multiphase coexistence exhibited facilitated domain switching, it was also bothered by reduced effectively reoriented domains and increased back-switching of already reoriented domains. Therefore, understanding the related physical mechanism is helpful to the further design of high-performance KNN-based ceramics used for electronic devices.