Physical Properties and Negative Thermal Property of Antiperovskite Mn3Ga0.5Sn0.5N

The crystal structure, thermal expansion, magnetic order and thermal characteristics of solid-state sintering Mn 3 Ga 0.5 Sn 0.5 N compounds were investigated. The Mn 3 Ga 0.5 Sn 0.5 N compound showed negative thermal expansion (NTE) behavior. Its coefficient of thermal expansion (CTE) is – 1.1×10 ⁻⁶ K ⁻¹ with an operation-temperature window of 60 K from 398K to 458 K. The Sn chemical element doping lead to latent heat of Mn 3 Ga 0 . 5 Sn 0.5 N compound smaller than that of Mn 3 Ga 0.5 N compound. From point of electrons, Sn element can supply more valence than that of the Ga element into Mn 3d -N 2p bond. The behavior of Sn element can affect the |E F − E S | parameter, which may determine whether structural transformation generally is a first-order phase transition. in the triangle Γ5g magnetic structure, Sn element becomes a little less efficient anti-ferromagnetic exchange interaction of the nearest-neighbor Mn-Mn moments, but beneficial for the ferromagnetic exchange interaction of the next nearest-neighbor Mn-Mn moments. This result may be helpful for understanding the mechanism of the class antiperovskite NTE material.