Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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Double-peak specific heat and spin freezing in the spin-2 triangular lattice antiferromagnet FeAl2Se4
Li, K.; Jin, S.; Guo, J.; Xu, Y.; Su, Y.; Feng, E.; Liu, Y.; Zhou, S.; Ying, T.; Li, S.; Wang, Z.; Chen, G.; Chen, X.;
We report the properties of a triangular lattice iron-chalcogenide antiferromagnet FeAl2Se4.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 0.4 K. Similar to the well-known spin-1 magnet NiGa2S4, the specific heat of FeAl2Se4 exhibits a double-peak structure and a T2 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 ∼14 K, 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 FeAl2Se4. Our results provide useful insights about the magnetic properties of frustrated quantum magnets with high spins.

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Publ.-Id: 28974 - Permalink