文献类型：期刊文献

英文题名：Valence state of the chromium ion and electrical conductivity of Ca-doped lanthanum chromite

作者：Zhang, GJ; Jia, YQ

机构：[1]E China Univ Sci & Technol, Dept Chem, Shanghai 200237, Peoples R China

年份：1999

卷号：215

期号：2

起止页码：1057

外文期刊名：PHYSICA STATUS SOLIDI B-BASIC RESEARCH

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000083233000024)】；

语种：英文

摘要：The valence state of the Cr ion in Ca-doped lanthanum chromite compounds without or with oxygen deficiency has been calculated by means of a tight-binding approximation on the basis of the EHMO approximation. The results indicate that the relative content of Cr4+ ions in La1-xCaxCrO3 will become larger with increasing x and the electrical conductivity is in proportion with the relative content of Cr4+ ions in the compound. The difference between some reported experimental results in the same compounds is mainly due to the different oxygen deficiency in the samples. Doping can lead not only to a splitting of the t(2g) and e(g) subbands from the Cr atom and a narrowing of the gap between the t(2g) subband from the Cr atom and 2p band from the O atom, but also leads to an increase of the relative content of the acceptor of Cr4+ ions and to an increasing number of holes in the band. A linear relationship between the electrical conductivity and the relative Cr4+ ion content may be valid only for lanthanum chromite with a small amount of Ca.