Thermomigration kinetics and a novel method to determine the chemical diffusivity of a mixed conductor
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- 作者：Taewon Lee ; Han-Ill Yoo ; hiyoo@snu.ac.kr
- 关键词：Thermomigration ; Chemical diffusivity ; Mixed ionic electronic conductor ; BaCo0.70Fe0.22Nb0.08O3 ; &minus ; ; δ ; Thermopower ; Heats-of-transport
- 刊名：Solid State Ionics
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：300
- 期：Complete
- 页码：212-218
- 全文大小：1215 K
- 卷排序：300
文摘
The kinetics of temperature-gradient-induced nonstoichiometry redistribution or δ-thermomigration of a mixed ionic electronic conductor, e.g., ABOν + δ has been solved analytically in closed form over the entire time span for the first time ever and hence, the temporal behaviors of the measurable, ionic and electronic thermovoltages. The latter allow one to determine the chemical diffusivity of the mobile component, say, O, in addition to the entropic quantities governing the thermomigration, under a temperature gradient more simply and easily compared to the conventional relaxation method under an oxygen potential gradient. The validity and workability of the novel method has been demonstrated by measuring the chemical diffusivity on the system of BaCo0.70Fe0.22Nb0.08O3 − δ and comparing with those as measured conventionally. The advantage of the novel method is discussed in comparison with the conventional relaxation method.