Unconventional spin freezing and fluctuations in the frustrated antiferromagnet NiGa2S4
| Autor: | MacLaughlin, D. E., Nambu, Y., Nakatsuji, S., Heffner, R. H., Shu, Lei, Bernal, O. O., Ishida, K. |
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| Rok vydání: | 2008 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.78.220403 |
| Popis: | Muon spin rotation (muSR) experiments reveal unconventional spin freezing and dynamics in the two-dimensional (2D) triangular lattice antiferromagnet NiGa2S4. Long-lived disordered Ni-spin freezing (correlation time > 10-6 s at 2 K) sets in below T_f = 8.5 +- 0.5 K with a mean-field-like temperature dependence. The observed exponential temperature dependence of the muon spin relaxation above T_f is strong evidence for 2D critical spin fluctuations. Slow Ni spin fluctuations coexist with quasistatic magnetism at low temperatures but are rapidly suppressed for fields > 10 mT, in marked contrast with the field-independent specific heat. The muSR and bulk susceptibility data indicate a well-defined 2D phase transition at T_f, below which NiGa2S4 is neither a conventional magnet nor a singlet spin liquid. Comment: 5 pages, 4 figures, to be published in Phys. Rev. B |
| Databáze: | arXiv |
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