Near zero thermal expansion properties in antiperovskite Mn3Cu0.6Ge0.4N prepared by spark plasma sintering

Abstract

Antiperovskite manganese nitride Mn3Cu0.6Ge0.4N was fabricated by spark plasma sintering (SPS) at different temperatures and its negative thermal expansion behavior was investigated. It is observed that the width of negative thermal expansion (NTE) operation-temperature window becomes broader when the sintering temperature decreases. Moreover, it is significantly larger than that of other Mn3CuN-based antiperovskite manganese nitrides prepared by solid-state reaction. More interestingly, the Mn3Cu0.6Ge0.4N sintered at 650°C shows near zero thermal expansion (ZTE) behavior in the temperature range of 220–170K. The average linear coefficient of thermal expansion (CTE) is estimated to be −0.9×10−6K−1. Magnetic measurement shows that the process of the magnetic transition becomes slow when the sintering temperature decreases. This antiperovskite manganese nitride Mn3Cu0.6Ge0.4N with ZTE behavior is much useful for applications in the fields of cryogenics and applied superconductivity.