Large plastic deformability of bulk ferroelectric KNbO3 single crystals

Marion Höfling*, Maximilian Trapp, Lukas Porz, Hana Uršič, Enrico Bruder, Hans Joachim Kleebe, Jürgen Rödel, Jurij Koruza

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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 010pc and 101pc 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.

Original languageEnglish
Pages (from-to)4098-4107
Number of pages10
JournalJournal of the European Ceramic Society
Issue number7
Publication statusPublished - Jul 2021
Externally publishedYes


  • Ferroelectric
  • KNbO
  • Plastic deformation
  • Single crystal

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

Fields of Expertise

  • Advanced Materials Science


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