Ab initio investigation of the non-collinear magnetic structure and the lowest magnetic excitations in dysprosium triangles

Abstract

The unusual magnetism exhibited by dysprosium triangles [Dy₃(μ₃-OH)₂L₃Cl₂(H₂O)₄][Dy₃(μ₃-OH)₂L₃Cl(H₂O)₅]Cl₅·19H₂O is explained using the recently developed ab initio methodology for the simulation of magnetic properties of complexes. The local anisotropy axes on the dysprosium sites are found to lie in the plane of the Dy₃ triangle and to make angles of ca. 120° with each other. The small antiferromagnetic exchange interaction between sites leads to a non-magnetic Kramers doublet in the ground state of the complex. The arrangement of the local magnetization vectors in this state is close to toroidal. By contrast, the lowest excited states are characterized by a huge magnetic moments of ca. 20 μ_B and show very different behavior of magnetization for fields applied along and perpendicular to the plane of the Dy₃ triangle.