Zintl相热电材料纳米晶(Mg_(0.97)X_(0.03))_3Sb_2的低温电输运性能  

Electrical Transport Properties of Nanocrystalline Zintl Phase(Mg_(0.97)X_(0.03))_3Sb_2 as Thermoelectric Materials

作　　者：辛红星[1] 秦晓英[1] 张宽心[1] 宋春军[1] 张建[1] 朱晓光[1] 

机构地区：[1]中科院固体物理研究所材料物理重点实验室,安徽合肥230031

出　　处：《材料科学与工程学报》2010年第2期244-247,243,共5页Journal of Materials Science and Engineering

基　　金：国家自然科学基金资助项目(50701043)

摘　　要：采用机械合金化结合热压的方法,制备了纳米晶(Mg0.97X0.03)3Sb2(X=Mg、Cr、Cu、Ti),进行了微结构表征和电阻率测量。结果表明其平均晶粒尺寸不超过40nm。(Mg0.97X0.03)3Sb2晶体结构四面体位置的Mg-Sb结合距离变短,共价性增强。室温电阻从543Ωcm(Mg3Sb2)下降到137Ωcm((Mg0.97Cr0.03)3Sb2)、121Ωcm((Mg0.97Ti0.03)3Sb2)、109Ωcm((Mg0.97Cu0.03)3Sb2)。替代样品的电阻在低温时为变程跳跃电导。电阻率的降低是由于替代形成的晶格中化学环境变化,原子间结合强度增加所致。Mechanical alloying plus hot-pressing was employed to prepare nanocrystalline（Mg 0.97 X 0.03）3Sb2（X=Mg、Cr、Cu、Ti）compounds which were characterized by microstructural examinations and DC electrical resistance measurements.The results indicated that mean grain size of（Mg 0.97 X 0.03）3Sb2 compounds is smaller than 40nm.The distance between Mg-Sb of the tetrahedral positions decreases and the strength of covalent bond increases in the lattice of（Mg 0.97 X 0.03）3Sb2.It can be seen that the resistivity of nano-（Mg 0.97 X 0.03）3Sb2 decreases from 543Ωcm（Mg3Sb2）to 137Ωcm（（Mg 0.97 Cr 0.03）3Sb2）、121Ωcm（（Mg 0.97 Ti 0.03）3Sb2）、109Ωcm（（Mg 0.97 Cu 0.03）3Sb2）at 300K.Variable range hopping conduction happens at low temperature for the substituted samples.The decreasing of electrical resistivity is due to the changed chemical surrounding and the enhanced bond strength in the lattice of the substituted samples.

关 键 词：机械合金化 纳米晶 替代 电阻率 变程跳跃电导 

分 类 号：O472.4[理学—半导体物理]