Origin of Colossal Dielectric Behavior In Double Perovskite Ba 2 CoNbO 6

作者：Guojing Wang, Chunchang Wang, Shouguo Huang, Changmei Lei, Xiaohong Sun, Teng Li, Lina Liu · 发表于：Journal of the American Ceramic Society · 年份：2013 · DOI：10.1111/jace.12318 · 被引用次数：26 · 研究领域：Dielectric properties of ceramics、Ferroelectric and Piezoelectric Materials、Multiferroics and related materials

Ba 2 CoNbO 6 ceramic samples were synthesized by solid‐state reaction technique. X‐ray photoemission spectroscopy reveals the coexistence of mixed‐valent structure of Co 2+ / Co 3+ in the sample. Dielectric measurements reveal that the sample shows colossal dielectric behavior. This behavior is contributed by two thermally activated dielectric relaxations: the low‐temperature relaxation is a polaron relaxation resulting from the hopping motions of self‐trapped holes; the high‐temperature relaxation is a Maxwell–Wagner relaxation caused by the grain‐boundary response. Our results indicate a multirelaxation mechanism, i.e., the coupling of the polaronic relaxation and the Maxwell–Wagner relaxations might be a common origin of the colossal dielectric behavior found in different materials.