Packing fraction related distortion of Mn sub(6) C octahedra and its effect on the first order magnetic transition in Mn based antiperovskites

Abstract

In this paper, we attempt to understand the cause of magnetostructural transformation in Mn-based antiperovskites by calculating extended x-ray absorption fine structure at the K edges of constituent metal atoms in three antiperovskite compounds, Mn sub(3) GaC, Mn sub(3) SnC, and Mn sub(3) InC. These three compounds have very different magnetic ground states despite the similar cubic structure. Our calculations show that the distortions of Mn sub(6) C octahedra, which are responsible for the first-order magnetic transition to the antiferromagnetic state, depend on the packing fraction of the lattice.