Yb_(14)MnSb_(11)单晶团簇的制备及其热电性能(英文)

Preparation and Thermoelectric Properties of Yb_(14)MnSb_(11) Single Crystal Clusters

本文采用Sn助熔剂法制备了近似于Yb14MnSb11单晶的单晶团簇,并用X射线衍射、扫描电镜及能谱对其物相和结构进行表征,同时还讨论了单晶团簇的生长机理。从室温到773K,单晶团簇的电阻率在室温下约为2～3mohm.cm,且随着温度的增加而逐渐变大;在700K以上,各试样间电阻率的偏差明显增大。另外,室温时Seebeck系数为45μV/K,并随着温度升高而增大,但温度高于～730K后Seebeck系数迅速降低。这种Yb14MnSb11单晶团簇的电传输性能在高温时的突变认为是由于其内部夹杂的Sn引起的。

Yb 14 MnSb 11 single crystal clusters were prepared by a Sn-flux method.X-ray diffractometry,scanning electron microscopy and electron dispersive X-ray spectroscopy were used for characterizing the Yb 14 MnSb 11 single crystal clusters.Growth mechanism of the crystal clusters was discussed.Electrical transport properties were measured directly on the single crystal clusters from room temperature to -773 K and compared with previously reported results for polycrystalline samples.The electrical resistivity of the single crystal clusters is -2-3 mohm·cm at 300 K and increases gradually in all the temperature range measured,but the deviation of the resistivity obviously increases at T 700 K.Their Seebeck coefficient,which is - 45 μV/K at 300 K,monotonically increases with temperature from 300 to -730 K and then quickly decreases with increasing temperature.Quick change of the electrical transport properties at high temperatures is considered to be due to the effect of the Sn-flux encapsulated in the crystals.