Effect of partial void filling on the transport properties of NdxCo4Sb12 skutterudites
Effect of partial void filling on the transport properties of NdxCo4Sb12 skutterudites
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DOI：
10.1088/0953-8984/15/29/315
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发表时间：
2003-07-30
影响因子：
2.7
通讯作者：
Rowe, DM
中科院分区：
文献类型：
--
作者：
Kuznetsov, VL;Kuznetsova, LA;Rowe, DM
制备了部分填充的角长石NdxCo4Sb12的多晶样品，并用x射线粉末衍射和差热分析对其进行了表征。在CoSb3中发现Nd空隙填充的饱和极限在13%左右。所有样品在1149 +/- 6k温度下不一致分解。室温霍尔测量表明，每个Nd原子提供约0.8个电子，明显小于Nd氧化态（3+）。在11-700 K范围内测量了电输运和热输运性质的温度依赖性。电阻率和塞贝克系数绝对值随Nd含量的增加而减小，对于x > 0.02的样品，温度依赖性是典型的重掺杂半导体。用Nd填充CoSb3会导致晶格热导率的快速下降，在Nd0.1Co4Sb12组成时最小。与其他部分填充的方块石相比，Nd填充方块石的晶格热导率在x < 0.1处最低，这可能是由于Nd填充元素的半径比其他填充元素小。在高温下，由于载流子浓度较低而导致的内禀导电，掺钕的方突石的ZT值受到限制。在势热电材料的背景下，讨论了部分Nd填充对填入的方钨矿化合物输运性质的影响。
Polycrystalline samples of the partially filled skutterudites NdxCo4Sb12 have been prepared and characterized by x-ray powder diffraction and differential thermal analysis. The saturation limit of the Nd void filling in CoSb3 was found to be around 13%. All samples decompose incongruently at a temperature of 1149 +/- 6 K. Room temperature Hall measurements show that each Nd atom donates approximately 0.8 electrons, which is significantly less than the Nd oxidation state (3+). The temperature dependence of the electrical and thermal transport properties has been measured over the range of 11-700 K. The electrical resistivity and absolute value of the Seebeck coefficient decrease with increasing Nd content and for samples with x > 0.02 the temperature dependence is typical of heavily doped semiconductors. Filling CoSb3 with Nd causes a rapid initial decrease in the lattice thermal conductivity with a minimum at the composition Nd0.1Co4Sb12. Nd-filled skutterudites exhibit the lowest value of the lattice thermal conductivity in comparison with other partially filled skutterudites at x < 0.1, which could be attributed to a smaller radius of Nd than that of other filling elements. At high temperature the ZT value of the Nd-filled skutterudites is limited due to intrinsic conduction caused by the relatively low carrier concentration. The effect of the partial Nd filling on the transport properties of the filled skutterudite compounds is discussed in the context of potential thermoelectric materials.