Anionic conductivity and thermal stability of single crystals of solid solutions based on calcium fluoride |
| |
| Affiliation: | 1. Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA;2. College of Materials Science and Engineering, Hunan University, Changsha 410082, China;3. Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249, USA |
| |
| Abstract: | The temperature and composition dependencies of the anionic conductivity in the temperature range from ambient to 1073 K were studied for single crystals of Ca1−xGdxF2+x (x=1×10−4, 1×10−3, 1×10−2 and 1×10−1) and of Ca0.8R0.2F2.2 (R=La, Ce, Pr, Nd, Gd, Dy, Er, Tm, Yb, Lu and Y), having the fluorite structure. The conductivity plots for the concentrated Ca0.8R0.2F2.2 solid solutions display the low-temperature and high-temperature linear (Arrhenius) regions with the knee temperature Tk∼770 K. The values of the conductivity activation enthalpy obey the relation ΔHHT(T>Tk)>ΔHLT(T<Tk). The conductivity mechanism in heavily doped Ca1−xRxF2+x crystals is associated with the clusters of the point defects which decrease the potential barriers for fluoride anions moving by hops over the structural sites of the anion sub-lattice. We studied the effect of the dimensional factor (doped cation radii) on the anionic transport in these crystals. A correlation between anionic transport and atomic structure of the studied crystals is discussed. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
