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Full Record for Micrograph 664
- Micrograph no
- 664
- Brief description
- Barium titanate ceramic
- Keywords
- barium, barium titanate, ceramic
, ferroelectric domain, herringbone domain structure, twinning - Categories
- Ceramic
- System
- BaTiO3
- Composition
- Not specified
- Standard codes
- Reaction
- Processing
- Applications
- Sample preparation
- Technique
- Reflected light microscopy
- Length bar
- No length bar
- Further information
- The ferroelectric domains are crystallographic twins which form on cooling the material through the paraelectric (cubic) to ferroelectric (tetragonal) phase transformation at 130ºC. Each grain is mechanically 'clamped' by its neighbours, which prevents it from developing the full tetragonal distortion and results in a state of residual, or 'internal', stress. Twinning reduces this residual stress and thereby reduces the free energy of the material.
The domain pattern shown was obtained by sectioning a bulk ceramic specimen with a diamond saw, followed by polishing and chemical etching to reveal the domain structure. The material was subsequently heated to a temperature above the ferroelectric phase transition, cooled to room temperature, re-polished and etched. The micrograph shows the sample after this intermediate 'de-twinning' process. The grains at the surface have adopted a domain configuration associated with the clamping condition of a grain at the surface. - Contributor
- Prof G Arlt
- Organisation
- Department of Materials Science, University of Manchester and UMIST
- Date
- 07/11/02
- Licence for re-use
DoITPoMS standard terms of use- Related micrographs