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Nanoscale compositional segregation and suppression of polar coupling in a relaxor ferroelectric
- Source :
- Acta Materialia. 158:422-429
- Publication Year :
- 2018
- Publisher :
- Elsevier BV, 2018.
-
Abstract
- A number of relaxor ferroelectric ceramics have been demonstrated to possess a near stable value of relative permittivity over very wide temperature ranges. This cannot be explained by conventional theories of relaxors. One such system is based on the perovskite solid solution series: (1-x) (Ba 0.8 Ca 0.2 )TiO 3 -xBi(Mg 0.5 Ti 0.5 )O 3 , giving stable relative permittivity from 150 to 500 °C. We show by scanning transmission electron microscopy and electron energy loss spectroscopic elemental mapping that nanoscale compositional segregation occurs in the temperature stable relaxor composition (x = 0.55), with Ba/Ti clusters some 2–4 nm in extent, separated by Bi-rich regions of comparable size. This nanomosaic structure is consistent with phase separation into a ferroelectrically active BaTiO 3 – type phase (Ba/Ti rich) and a weakly polar Bi/(Mg) rich perovskite solid solution. The possibility that nanophase segregation is the cause of weak dipole coupling and suppression of the dielectric relaxation peak is considered.
- Subjects :
- 010302 applied physics
Materials science
Polymers and Plastics
Metals and Alloys
Relative permittivity
02 engineering and technology
Dielectric
Atmospheric temperature range
021001 nanoscience & nanotechnology
01 natural sciences
Ferroelectricity
Electronic, Optical and Magnetic Materials
Chemical physics
Phase (matter)
0103 physical sciences
Scanning transmission electron microscopy
Ceramics and Composites
0210 nano-technology
Perovskite (structure)
Solid solution
Subjects
Details
- ISSN :
- 13596454
- Volume :
- 158
- Database :
- OpenAIRE
- Journal :
- Acta Materialia
- Accession number :
- edsair.doi.dedup.....085a44bb7ffa7d7eb31d5be096151c89