Cerium filling and doping of cobalt triantimonide

作者：Donald T. Morelli, G. P. Meisner, Baoxing Chen, Siqing Hu, Ctirad Uher · 发表于：Physical review. B, Condensed matter · 年份：1997 · DOI：10.1103/physrevb.56.7376 · 被引用次数：388 · 研究领域：Rare-earth and actinide compounds、Physics of Superconductivity and Magnetism、Semiconductor materials and interfaces

We have fabricated and studied the structural, magnetic, and transport properties of filled skutterudites of the form ${\mathrm{Ce}}_{y}{\mathrm{Fe}}_{4\ensuremath{-}x}{\mathrm{Co}}_{x}{\mathrm{Sb}}_{12}$ with 0 $y$1 and $x$=3.25 and 4. For samples containing 100% Co, Ce can be inserted into approximately 10% of the voids in the skutterudite structure. It is shown that the rare earth is trivalent and dopes the host Co${\mathrm{Sb}}_{3}$ $n$-type. With substitution of Fe for Co the void occupancy by Ce increases. The thermal conductivity is strongly depressed even at small (5%) rare-earth filling fractions, and is further degraded by substitution of Fe for Co. Although the electron mobility in $n$-type samples is smaller than the hole mobility in $p$-type samples, due to their large electron masses the Seebeck coefficient in $n$-type material maintains large values at high electron concentrations.