Large plastic deformability of bulk ferroelectric KNbO3 single crystals. Issue 7 (July 2021)

• Record Type: Journal Article
• Authors: Höfling, Marion; Trapp, Maximilian; Porz, Lukas; Uršič, Hana; Bruder, Enrico; Kleebe, Hans-Joachim; Rödel, Jürgen; Koruza, Jurij
• Is Part Of: Journal of the European Ceramic Society. Volume 41:Issue 7(2021)
• Page Start: 4098
• Page End: 4107
• Publication Date: 2021-07
• Subjects: KNbO3 -- Single crystal -- Ferroelectric -- Plastic deformation; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2021.02.023
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Ferroelectrics have become indispensable electroceramic materials in modern electronic applications. While point-defect engineering is a common tool to modify the properties of ferroelectrics, dislocations have not been widely considered, although they were previously shown to alter electrical properties in other oxides. Here, we study the room temperature uniaxial deformation of the perovskite ferroelectric single crystalline KNbO3 in 010 p c and 101 p c orientations. We demonstrate a large plastic deformation in the range of 5%. Dislocation and domain structure were investigated across different length scales using optical microscopy, electron channeling contrast imaging, and transmission electron microscopy. Planar arrangement of dislocations in slip bands was observed, while the predominant appearance of edge dislocations indicates a dominant dislocation motion by the kink-pair mechanism. Increased dislocation density resulted in decreased ferroelectric domain size from 1.8 μm to 0.5 μm after deformation. Piezoresponse force microscopy highlights the effect of dislocations on domain nucleation and their mobility.