Spin Chirality in a Molecular Dysprosium Triangle: The Archetype of the Noncollinear Ising Model

Abstract

Single crystal magnetic studies combined with a theoretical analysis show that cancellation of the magnetic moments in the trinuclear ${\mathrm{Dy}}^{3+}$ cluster $[{\mathrm{Dy}}_{3}({\ensuremath{\mu}}_{3}\mathrm{\text{\ensuremath{-}}}\mathrm{OH}{)}_{2}{\mathrm{L}}_{3}\mathrm{Cl}({\mathrm{H}}_{2}\mathrm{O}{)}_{5}]{\mathrm{Cl}}_{3}$, resulting in a nonmagnetic ground doublet, originates from the noncollinearity of the single-ion easy axes of magnetization of the ${\mathrm{Dy}}^{3+}$ ions that lie in the plane of the triangle at 120\ifmmode^\circ\else\textdegree\fi{} one from each other. This gives rise to a peculiar chiral nature of the ground nonmagnetic doublet and to slow relaxation of the magnetization with abrupt accelerations at the crossings of the discrete energy levels.