Near zero thermal expansion in Ge-doped Mn3GaN compounds

Abstract

The antiperovskite Mn3Ga1−xGexN (x=0, 0.1, 0.2, 0.3, 0.4 and 0.5) compounds were prepared by a method of solid-state sintering at 860°C under a nitrogen atmosphere for 24h. The Mn3Ga1−xGexN compounds were characterized by X-ray diffraction, thermal dilatometer and physical property measurement system (PPMS), respectively. The experimental results indicate that the starting temperature of negative thermal expansion (NTE) is obviously moved toward a higher temperature region with the increase of Ge content. Meanwhile, the absolute value of coefficient of NTE (|α|) decreases continuously. Accordingly, the near zero thermal expansion (ZTE) behavior is explored at an approximate temperature range of 423–475K for Mn3Ga0.5Ge0.5N. Furthermore, the mechanism of ZTE is also discussed. The present ZTE behavior serves as a valuable example for demonstrating the promise of exploring other potential ZTE materials in the family of antiperovskite manganese nitrides.