Emergence of noncollinear magnetic ordering in small magnetic clusters: Mn_n and As@Mn_n

Abstract

Using first-principles density functional calculations, we have studied the magnetic ordering in pure Mn_n (n=2-10,13,15,19) and As@Mn_n (n=1-10) clusters. Although, for both pure and doped manganese clusters, there exists many collinear and noncollinear isomers close in energy, the smaller clusters with n≤5 have collinear magnetic ground states and the emergence of noncollinear ground states is seen for n≥6 clusters. Due to strong p-d hybridization in As@Mn_n clusters, the binding energy is substantially enhanced and the magnetic moment is reduced compared to the corresponding pure Mn_n clusters.