Unusual double-peak specific heat and spin freezing in a spin-2 triangular lattice antiferromagnet FeAl${}_2$Se${}_4$

Abstract

We report the properties of a triangular lattice iron-chalcogenide antiferromagnet FeAl${}_2$Se${}_4$. The spin susceptibility reveals a significant antiferromagnetic interaction with a Curie-Weiss temperature Θ${}_{CW}$ ~ -200K and a spin-2 local moment. Despite a large spin and a large |Θ${}_{CW}$|, the low-temperature behaviors are incompatible with conventional classical magnets. No long-range order is detected down to 0.4K. Similar to the well-known spin-1 magnet NiGa${}_2$S${}_4$, the specific heat of FeAl${}_2$Se${}_4$ exhibits an unusual double-peak structure and a T${}^2$ power law at low temperatures, which are attributed to the underlying quadrupolar spin correlations and the Halperin-Saslow modes, respectively. The spin freezing occurs at ~ 14K, below which the relaxation dynamics is probed by the ac susceptibility. Our results are consistent with the early theory for the spin-1 system with Heisenberg and biquadratic spin interactions. We argue that the early proposal of the quadrupolar correlation and gauge glass dynamics may be well extended to FeAl${}_2$Se${}_4$. Our results provide useful insights about the magnetic properties of frustrated quantum magnets with high spins.

7 pages, 4 figures

References in corpus (14)

• Spin-Liquid State in the S = 1/2 Hyperkagome Antiferromagnet Na4Ir3O8
• Continuous excitations of the triangular-lattice quantum spin liquid YbMgGaO4
• Mott Transition from a Spin Liquid to a Fermi Liquid in the Spin-Frustrated Organic Conductor kappa-(ET)2Cu2(CN)3
• Disorder-Induced Mimicry of a Spin Liquid in YbMgGaO${}_4$
• Possible ferro-spin nematic order in NiGa2S4
• Quadrupolar correlations and spin freezing in S = 1 triangular lattice antiferromagnets
• The Spinon Fermi Surface U(1) Spin Liquid in a Spin-Orbit-Coupled Triangular Lattice Mott Insulator YbMgGaO4
• Spin Liquid versus Spin Orbit Coupling on the Triangular Lattice
• Hidden multipolar orders of dipole-octupole doublets on a triangular lattice
• A single crystal high-temperature pyrochlore antiferromagnet
• Selective measurements of intertwined multipolar orders: non-Kramers doublets on a triangular lattice
• Topological Paramagnetism in Frustrated Spin-One Mott Insulators
• Ghost in the machine: Theory of inelastic neutron scattering in a field-induced spin-nematic state
• Halperin-Saslow modes as the origin of the low temperature anomaly in $NiG{a}_2{S}_4$

Cited by in corpus (4)

• Gapless triangular-lattice spin-liquid candidate in PrZnAl${}_{11}$O${}_{19}$
• Origin of the hidden energy scale and the $f$-ratio in geometrically frustrated magnets
• Emergent Halperin-Saslow mode and Gauge Glass in quantum Ising magnet TmMgGaO${}_4$
• Quantum spin liquid ground state with the evidence of roton-like excitations at elevated temperatures in the triangular-lattice delafossite YbCuSe${}_2$