Decisive role of mixed-valence structure in colossal dielectric constant of LaFeO3
The role of mixed-valence structure in colossal dielectric constant (CDC) behavior has been investigated in LaFeO 3 ceramics by tuning the ratio of Fe 2+ /Fe 3+ through substituting Al for Fe. The ratio of Fe 2+ /Fe 3+ is decreased gradually from 1.0 to 0.0 by increasing the concentration of Al 3...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Journal Article |
| Published: |
Wiley-Blackwell Publishing, Inc.
2017
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| Online Access: | http://hdl.handle.net/20.500.11937/57000 |
| Summary: | The role of mixed-valence structure in colossal dielectric constant (CDC) behavior has been investigated in LaFeO 3 ceramics by tuning the ratio of Fe 2+ /Fe 3+ through substituting Al for Fe. The ratio of Fe 2+ /Fe 3+ is decreased gradually from 1.0 to 0.0 by increasing the concentration of Al 3+ . Two clear-cut correlations have been found: (i) the relationship between the CDC behavior and the ratio of Fe 2+ /Fe 3+ follows an exponential function and (ii) the activation energy of the polaron relaxation is proportional to 1/? 2 0 , where ? 0 is the intrinsic dielectric constant. These findings underscore the role of the mixed-valence structure in CDC behavior and suggest that adjusting the mixed-valence structure through doping/alloying can be a promising strategy to achieve superior CDC behavior in transition-metal oxides. |
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