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Decisive role of mixed‐valence structure in colossal dielectric constant of LaFeO3 |
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| Authors: | Wei Ni Jianglin Ye Youmin Guo Chao Cheng Zhongqin Lin Yide Li Hong Wang Yi Yu Qiuju Li Shouguo Huang Zongping Shao Chunchang Wang |
| Affiliation: | 1. Laboratory of Dielectronic Functional Materials, School of Physics and Material Science, Anhui University, Hefei, China;2. Center of Modern Experimental Technology, Anhui University, Hefei, China;3. Jiangsu National Synergetic Innovation Center for Advanced Material, College of Energy, State Key Laboratory of Materials‐Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China;4. Department of Chemical Engineering, Curtin University, Perth, WA, Australia |
| Abstract: | The role of mixed‐valence structure in colossal dielectric constant (CDC) behavior has been investigated in LaFeO3 ceramics by tuning the ratio of Fe2+/Fe3+ through substituting Al for Fe. The ratio of Fe2+/Fe3+ is decreased gradually from 1.0 to 0.0 by increasing the concentration of Al3+. Two clear‐cut correlations have been found: (i) the relationship between the CDC behavior and the ratio of Fe2+/Fe3+ follows an exponential function and (ii) the activation energy of the polaron relaxation is proportional to  , where  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. |
| Keywords: | dielectric materials/properties dielectric relaxation |