Emergent order in the kagome Ising magnet Dy<sub>3</sub>Mg<sub>2</sub>Sb<sub>3</sub>O<sub>14</sub>.

Paddison, Joseph A M; Ong, Harapan S; Hamp, James O; Mukherjee, Paromita; Bai, Xiaojian; Tucker, Matthew G; Butch, Nicholas P; Castelnovo, Claudio et al. · Nat Commun · 2016

basic_science · Level V

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Abstract

The Ising model-in which degrees of freedom (spins) are binary valued (up/down)-is a cornerstone of statistical physics that shows rich behaviour when spins occupy a highly frustrated lattice such as kagome. Here we show that the layered Ising magnet Dy<sub>3</sub>Mg<sub>2</sub>Sb<sub>3</sub>O<sub>14</sub> hosts an emergent order predicted theoretically for individual kagome layers of in-plane Ising spins. Neutron-scattering and bulk thermomagnetic measurements reveal a phase transition at ∼0.3 K from a disordered spin-ice-like regime to an emergent charge ordered state, in which emergent magnetic charge degrees of freedom exhibit three-dimensional order while spins remain partially disordered. Monte Carlo simulations show that an interplay of inter-layer interactions, spin canting and chemical disorder stabilizes this state. Our results establish Dy<sub>3</sub>Mg<sub>2</sub>Sb<sub>3</sub>O<sub>14</sub> as a tuneable system to study interacting emergent charges arising from kagome Ising frustration.