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DF: Fachverband Dielektrische Festkörper

DF 19: Poster 2

DF 19.16: Poster

Mittwoch, 13. März 2013, 15:00–17:30, Poster B2

Piezoresponse force microscopy studies of (K,Na)NbO3-based ceramics for piezoactuator applications — •Danka Gobeljic¹, Vladimir V. Shvartsman¹, Ke Wang², Wook Jo³, Jing-Feng Li², Jürgen Rödel³, and Doru C. Lupascu¹ — ¹Institute for Materials Science, Universität Duisburg-Essen, Essen 45141, Germany — ²State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 10008, P.R. China — ³Institute of Materials Science, Technische Universität Darmstadt, Darmstadt 64287, Germany

One of the most promising, environmentally friendly, lead-free piezoceramics are (K,Na)NbO3 (KNN)-based materials. Purposeful doping makes KNN especially suitable for high-precision, temperature-stable actuator applications, providing high piezoelectric constant d33 and strain, which shows significant stability in a range from room temperature up to 175°C. We present results of a Piezoresponse Force Microscopy (PFM) study on 0.95(Na0.49K0.49Li0.02)(Nb0.8Ta0.2)O3-0.05CaZrO3 ceramics at different temperatures. For both poled and unpoled states of KNN samples a reorganization of domain structure was observed with temperature increase. It is related to a sequence of phase transformation in this material. Measured temperature dependences of the local longitudinal piezoelectric coefficients are in reasonable agreement with temperature behavior of the macroscopic low signal piezoelectric coefficient. Obtained results provide nanoscopic insight on mechanisms of enhanced electromechanical properties in the studied KNN-based ceramics.