Electronic structure and magnetism of RMn₆Sn₆ (R=Tb,Dy)

This article reports first-principles band structure calculations for RMn₆Sn₆ (R=Tb, Dy). The calculation uses the linear muffin-tin orbital (LMTO) method in the atomic-sphere-approximation (ASA), and yields results showing that both TbMn₆Sn₆ and DyRMn₆Sn₆ are ferrimagnetic compounds with antiparallel aligned moments of R and Mn atoms. In this research the 4f states of R atoms are treated as localized states, i.e., the hybridization of 4f states with other valence electrons is neglected. The moments of Mn in both compounds were determined to be 2.43 μ_B and 2.38 μ_B, respectively. The considerably small additional moments for Mn from the spin-orbit coupling indicates that the spin-orbital coupling is not dominated for Mn atoms. The total moments of Tb and Dy atoms are 10.28 μ_B and 11.20 μ_B. All the calculation findings accorded well with experimental results.