Influence of sample compaction on the thermoelectric performance of Zn4Sb3

Five compacted samples of thermoelectric Zn4Sb3 have been prepared from the same synthesis batch by spark plasma sintering. Four samples were made from powder with a grain size < 45 mu m, and one sample from powder with grain size > 45 mu m. Thermoelectric properties were evaluated, and an apparent strong correlation with sample density is found. ZnSb impurity contents obtained from powder x-ray diffraction cannot explain the variation in properties, which the authors' suggest may be caused by slight changes in Zn content. The results show that minute changes in sample compaction conditions can have a larger effect on ZT than doping. (c) 2006 American Institute of Physics.