本文采用Sn助熔剂法制备了近似于Yb_(14)MnSb_(11)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773 K,单晶团簇的电阻率在室温下约为2～3 mohm·cm,且随着温度的增加而逐渐变大;在700 K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～730 K后Seebeck系数迅速降低.这种Yb_(14)MnSb_(11)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.
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