Magnetic Properties and Electronic Structure of YbMnSi

YbMnSi was synthesized by annealing a stoichiometric mixture of elements at 800 °C for 2 weeks. The compound exhibits an orthorhombic TiNiSi‐type structure, in agreement with an earlier report. The Yb 3+ oxidation state is confirmed unambiguously by L 3 ‐edge X‐ray absorption spectroscopy. Two magnetic transitions are observed at 303 and 20 K by bulk magnetic measurements. The high‐temperature phase transition corresponds to antiferromagnetic (AFM) ordering of Mn 3 d magnetic moments while the low‐temperature one is attributed to ordering of Yb 4 f moments. Theoretical studies reveal the strong preference of this material toward AFM ordering of Mn moments, which leads to stabilization of the electronic structure by decreasing the density of states and antibonding Mn–Mn interactions at the Fermi level.