Trillium lattices, in which magnetic ions form a three-dimensional chiral network of corner-sharing equilateral triangular motifs, offer a prominent platform to explore exotic quantum states. In this work, we report ground-state properties of the $S=5/2$ trillium lattice compound ${\mathrm{K}}_2\mathrm{FeSn}{\left({\mathrm{PO}}_4\right)}_3$ through thermodynamic, electron spin resonance (ESR), and muon spin relaxation ($\mu \mathrm{SR}$) experiments. Thermodynamic and ESR measurements reveal the two-step evolution of magnetic correlations across $T^{*}=11\mathrm{K}$, which results from an interplay between dominant antiferromagnetic Heisenberg interactions and subleading interactions. Below $T^{*}$, dc and ac magnetic susceptibilities indicate weak magnetic ordering at $T_{\mathrm{N}}\approx 2\mathrm{K}$ under low fields, which is suppressed for ${\mu }_{0}H\ge 2$ T, consistent with a power-law dependence of magnetic specific heat at low temperatures. $\mu \mathrm{SR}$ experiments confirm the dominance of persistent spin dynamics and the absence of conventional spin freezing, supporting the subtle nature of weak magnetic ordering coexisting with strong spin fluctuations. These findings underscore the potential for realizing a classical spin-liquid ground state with exotic excitations in high-spin trillium lattice systems.

Close

PrevNext

View figure in article

• Frustrated magnetism
• High magnetic fields
• Magnetic susceptibility
• Magnetism
• Magnetization dynamics
• Topological materials
• Antiferromagnets
• Magnetic systems
• Electron spin resonance
• Muon spin relaxation & rotation