Charge motions and dynamics of relaxation
| Autor: | R.H. Cole |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Materials science
Condensed matter physics Shadow zone Complex system Ionic bonding Dielectric Viscous liquid Condensed Matter Physics Spectral line Electronic Optical and Magnetic Materials Universality (dynamical systems) Exponential function Computational physics Materials Chemistry Ceramics and Composites |
| Zdroj: | Journal of Non-Crystalline Solids. :1125-1130 |
| ISSN: | 0022-3093 |
| DOI: | 10.1016/0022-3093(91)90738-r |
| Popis: | This review of dielectric aspects of relaxation processes begins with a survey of current experimental capabilities. These now extend from 10−4 Hz to 1010 Hz with comparative ease and good resolution by broad band methods. The increasing difficulties of measurements from much above 1010 Hz to 1012 Hz or more are considered together with the prospects for improvement. The need for and value of information in this ‘shadow zone’ is illustrated by several examples. Some limitations of dielectric probes of relaxation in general and of charge displacement in particular in relation to other approaches are indicated before turning to discussion of several classes of complex systems. Viscous liquids and their approach to their glass transitions are discussed, with particular attention to choice of representative examples and the need for studies of liquids composed of simpler molecules in order better to distinguish universality and individuality. Various possible origins of ‘excess absorption’ at higher frequencies other than stretched exponential or skewed arc behavior are also considered in this context. Two classes of molecular crystals that exhibit orientational relaxation effects, hydrogen halides and chlorinated methyl benzenes, receive attention because they both show changes from asymmetric to broad symmetric characteristic relaxation spectra associated with the state of order which may have more general implications. Problems with representation and interpretation of data for charge transport in ionic conducting glasses are indicated, with an indication of considerations to be kept in mind in resolving problems for conducting dielectrics generally, as are other generalities about dielectric and charge transport problems. |
| Databáze: | OpenAIRE |
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