中文摘要：

通过变温X射线衍射技术研究了反钙钛结构Mn3XN（X=Ga,Zn,Sn,Cu）化合物的热膨胀性质。随着温度的升高,此类材料在磁相变附近有时会伴随大的晶格收缩,即负热膨胀效应。尽管如此,晶格收缩并不总是发生,如：Mn3ZnN,Mn3CuN,Mn3SnN。对这种独特的热膨胀性质与X位置元素价电子数之间的关系进行了讨论。结果表明：3价元素更有利于此类化合物产生负热膨胀效应。通过X位置元素掺杂,可调控此类材料的负热膨胀系数和温区。Mn3Zn0.5Ge0.5N的负热膨胀系数可达-7.15×10^-6/K,温区扩展到100K左右。此外,还发现Mn3GaN和Mn3Zn0.7Sn0.3N在室温附近,晶胞常数随温度的升高几乎保持不变,显示为近零膨胀。

英文摘要：

The thermal expansion properties of anti-perovskite Mn3XN（X=Ga, Zn, Sn, Cu） compounds were investigated by X-ray diffraction at different temperatures, and a large negative thermal expansion effect in the compounds was observed. Near magnetic transition, abrupt lattice contraction such as Mn3ZnN, Mn3CuN, Mn3SnN does not always happen. The peculiar thermal expansion behavior of the compounds and its relationship with the different valence electrons at the X site were discussed. The results show that the abnormal thermal expansion behavior is related to the number of valence electrons at the X site and 3 valence electrons is beneficial to obtain a compound with negative thermal expansion. The negative thermal expansion coefficient value and the temperature range of the compound could be adjusted by doping at the X site in Mn3XN. For example, the negative thermal expansion temperature range of Mn3Zn0.5Ge0.5N can reach 100 K, with a thermal expansion coefficient of-7.15 × 10^-6/K. For MnaGaN and Mn3Zn0.7Sn0.3N, their lattice constants almost remain constant with the increase of temperature at around room temperature, implying the occurrence of near zero thermal expansion.