Broadened negative thermal expansion operation-temperature window in antiperovskite Mn3Zn0.6Ge0.4N prepared by spark plasma sintering

Abstract

Anti-perovskite manganese nitrides Mn3Zn0.6Ge0.4N with different crystallite size were prepared by spark plasma sintering (SPS) at different sintering temperatures. Their negative thermal expansion (NTE) properties were investigated. It was found that the width of NTE operation-temperature window (ΔT) broadens with decreasing crystallite size. Typically, a broad ΔT of 105K was obtained in the compound Mn3Zn0.6Ge0.4N with average crystallite size of 54nm sintered at 700°C, of which the average linear thermal expansion coefficient was estimated to be −13.5×10−6K−1 in the NTE operation-temperature window. This antiperovskite manganese nitride Mn3Zn0.6Ge0.4N with broadened ΔT around room temperature is more useful for practical applications.