Novel powder EPR lineshapes for KH2PO4(KDP)-type crystals
- Resource Type
- Authors
- N. S. Dalal
- Source
- Ferroelectrics. 39:1059-1059
- Subject
- Phase transition
Materials science
Condensed matter physics
Type (model theory)
Condensed Matter Physics
Molecular physics
Ferroelectricity
Spectral line
Electronic, Optical and Magnetic Materials
law.invention
Slow motion
law
Molecule
Crystallite
Electron paramagnetic resonance
- Language
- ISSN
- 1563-5112
0015-0193
Generally, the EPR spectra of solids undergoing phase transitions show features characteristic of either the “fast motion” or of the “slow motion” limit. In the spectra of the AsO4 4− radical in polycrystalline KH2AsO4 and related ferroelectric compounds, however, EPR spectra characteristic of both regimes have been observed. These new features have been interpreted in terms of discrete jumps of the AsO4 4− molecules. Here we propose an alternative explanation: the new features correspond to those parts of the “high temperature” sample in which the phase transition has already set in on the EPR time scale. New evidence based on the CrO4 3− and SeO4 3− probes supporting this viewpoint will be discussed. The results provide new insight into the microscopic picture of the phase transition phenomenon.