Evidence for an exotic magnetic transition in the triangular spin system FeGa2S4

Abstract

We report positive muon spin relaxation measurements on the triangular lattice magnetic system FeGa2S4. A magnetic transition not previously detected by specific heat and magnetic susceptibility measurements is found in zero field at T^* \simeq 30 K. It is observed through the temperature dependencies of the signal amplitude and the spin-lattice relaxation rate. This transition is therefore not a conventional magnetic phase transition. Since persistent spin dynamics is observed down to 0.1 K, the ground state cannot be of the canonical spin-glass type, which could be suggested from hysteresis effects in the bulk susceptibility below T_f \simeq 16 K. These results are compared to those found for the isomorph NiGa2S4. It is argued that the fate of the transition, which has been interpreted in terms of the Z_2 topological transition in this latter system, is probably different in FeGa2S4.

5 pages, 3 figures

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Cited by in corpus (8)

• Nd2Sn2O7: an all-in-all-out pyrochlore magnet with no divergence-free field and anomalously slow paramagnetic spin dynamics
• Evidence for unidimensional low-energy excitations as the origin of persistent spin dynamics in geometrically frustrated magnets
• Ground-state properties of the triangular-lattice Heisenberg antiferromagnet with arbitrary spin quantum number $s$
• Spin dynamics and spin freezing in the triangular lattice antiferromagnets FeGa2S4 and NiGa2S4
• Spin current as a probe of the ${\mathbb{Z}}_2$-vortex topological transition in the classical Heisenberg antiferromagnet on the triangular lattice
• Magnetic correlations in triangular antiferromagnet FeGa${}_2$S${}_4$
• Magnetic order, spin waves and fluctuations in the triangular antiferromagnet La2Ca2MnO7
• Unusual spin dynamics in the van der Waals antiferromagnet FeGa2S4