Emergent order in the kagome Ising magnet Dy3Mg2Sb3O14

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 Dy3Mg2Sb3O14 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 Dy3Mg2Sb3O14 as a tuneable system to study interacting emergent charges arising from kagome Ising frustration.

Structural and magnetic properties of two branches of the tripod-kagome-lattice familyA2R3Sb3O14(ADun1, Trinh2, Lee3 et al. 2017Phys. Rev. B4513583View full textAdd to dashboardCite

“…This signal is not likely due to the Dy nuclear spin given the same magnetic ion and same hyperfine coupling. One possibility is that it is related to the additional spin dynamics below the ECO, which has been proposed theoretically by Monte Carlo simulations 24,25 . Since the ECO state is a spin partially-ordered state, it contains a non-zero entropy density of 0.108R = 0.90 J/K per mole spin.…”

“…Recent neutron scattering experiments 25 illustrate that this LRO transition is actually an ECO where emergent magnetic charge degrees of freedom exhibit LRO while spins remain partially disordered. Thus, the partially disordered spins give an averaged LRO moment on each Dy site, which is the origin of the LRO features observed in χ ac and C mag .…”

“…For example, by comparing two separate reports of MgDy 15,25 , the difference of the ECO ordering temperatures (∼ 0.3 K in Ref. 25 , ∼ 0.37 K in Ref. 15 ) and the sharpness of the transition peaks in C(T ) can be attributed to the different percentages of Mg/Dy site disorder which might come from different reaction environments during sample synthesis.…”

“…It is also noteworthy that a small level of site disorder is likely to play an important role. For example, by comparing two separate reports of MgDy 15,25 , the difference of the ECO ordering temperatures (∼ 0.3 K in Ref. 25 , ∼ 0.37 K in Ref.…”

Clustering of Topological Charges in a Kagome Classical Spin Liquid

“…Below T c , where the kagome ice correlation is well developed, pinchpoint singularities are observed [ Fig. 3(b)], coexisting with the Bragg peaks of ferrimagnetic order [36,37,[44][45][46].…”