Packing fraction induced phase separation in A-site doped antiperovskites

Abstract

Local phase separation displayed by the A site doped Mn 3 Sn 1 − x A x C antiperovskites is investigated by studying a series of compounds wherein, the doped A site atoms inflicts changes in electronic contribution to the valence band while keeping the average size of the A site similar (In for Sn), or the size of the A-site atom is varied while maintaining the electronic density constant (Ge for Sn) or both, size and electronic density are varied (Zn for Sn). The study shows that the phase separation is a result of varied distortion of Mn 6 C octahedra due to the difference in the packing fractions of the unit cells. This distortions of the Mn 6 C octahedra are responsible for the observed magnetic properties of these antiperovskite compounds. • All A site substituted antiperovskite compounds, though have a cubic structure, display a local phase separation. • The Mn 6 C octahedra are distorted and the extent of distortion depends on the packing fraction of the unit cell. • Local phase separation and the distortions of the Mn 6 C octahedra play a decisive role in magnetic ground state of these antiperovskite compounds.