Domain Engineering of Lead‐Free Li‐Modified (K,Na)NbO3 Polycrystals with Highly Enhanced Piezoelectricity |
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Authors: | Ke Wang Jing‐Feng Li |
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Affiliation: | State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University Beijing 100084 (P.R. China) |
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Abstract: | Aging and re‐poling induced enhancement of piezoelectricity are found in (K,Na)NbO3 (KNN)‐based lead‐free piezoelectric ceramics. For a compositionally optimized Li‐doped composition, its piezoelectric coefficient d33 can be increased up to 324 pC N?1 even from a considerably high value (190 pC N?1) by means of a re‐poling treatment after room‐temperature aging. Such a high d33 value is only reachable in KNN ceramics with complicated modifications using Ta and Sb dopants. High‐angle X‐ray diffraction analysis reveals apparent changes in the crystallographic orientations related to a 90° domain switching before and after the aging and re‐poling process. A possible mechanism considering both defect migration and rotation of spontaneous polarization explains the experimental results. The present study provides a general approach towards piezoelectric response enhancement in KNN‐based piezoelectric ceramics. |
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Keywords: | ceramics doping electronic structures piezoelectricity structure– property relationships |
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