2008/03/06 by A. Yaouanc, P. Dalmas de Reotier, P. Dalmas de Réotier +7 · 1 citation
Physics and Astronomy · #Advanced Condensed Matter Physics #Physics of Superconductivity and Magnetism #Theoretical and Computational Physics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.77.092403
5 pages, 2 figures. Corrected typo at the end of the abstract
arxiv created 2008/03/06 · openalex publication_date 2008/03/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We report a study of the triangular-lattice Heisenberg magnet NiGa2S4 by the positive muon spin relaxation technique. We unravel three temperature regimes: (i) below Tc=9.2(2)\phantom\rule0.3em0exK, a spontaneous static magnetic field at the muon site is observed and the spin dynamics is appreciable: the time scale of the modes we probe is \ensuremath≃7\phantom\rule0.3em0exns; (ii) an unconventional stretched exponential relaxation function is found for Tc<T<Tcross, where Tcross=12.6\phantom\rule0.3em0exK, which is a signature of a multichannel relaxation for this temperature range; and (iii) above Tcross, the relaxation is exponential as expected for a conventional compound. The transition at Tc is of the continuous type. It occurs at a temperature slightly smaller than the temperature at which the specific heat displays a maximum at low temperature. This is reminiscent of the behavior expected for the Berezinskii--Kosterlitz--Thouless transition. We argue that these results reflect the presence of topological defects above Tc.