Dynamics at the ferroelectric to dipolar glass transition
Autor: | P. A. Fleury, K. B. Lyons |
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Rok vydání: | 1993 |
Předmět: |
Materials science
Condensed matter physics Niobium chemistry.chemical_element Soft modes Neutron scattering Condensed Matter Physics Ferroelectricity Electronic Optical and Magnetic Materials symbols.namesake Nuclear magnetic resonance chemistry Brillouin scattering symbols Glass transition Raman spectroscopy Raman scattering |
Zdroj: | Ferroelectrics. 144:17-31 |
ISSN: | 1563-5112 0015-0193 |
Popis: | We review our measurements on the polarization dynamics near the dipolar glass transition in KTN, at low niobium concentration (0.9-1.2%). Measurements over a wide range of characteristic times, including Raman and Neutron scattering, Brillouin scattering, ac dielectric response, and polarization decay, have revealed the presence of relaxation processes which vary over a very wide time range as the low concentration sample is cooled. At the higher concentration (1.2%) this behavior changes somewhat, showing evidence for the development of two transitions, at temperatures of about 15 K and 19-20 K, respectively. The dynamic signatures of the two transitions are different. The upper transition is characterized by a low frequency soft mode which exhibits a minimum in frequency as a function of temperature, but no evidence has been found for development of long-range ferroelectric order. The lower transition exhibits a divergent and singular central peak phenomenon. We speculate as to the origin of t... |
Databáze: | OpenAIRE |
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