Ultrasonic investigation of the quasi-2D quantum antiferromagnet Cs2CuCl4


Ultrasonic investigation of the quasi-2D quantum antiferromagnet Cs2CuCl4

Zherlitsyn, S.; Sytcheva, A.; Wosnitza, J.; Zvyagin, A. A.; Chiatti, O.; Coldea, R.

We report results of sound-velocity and sound-attenuation measurements in the triangularlattice quasi-two-dimensional spin-1/2 antiferromagnet (AFM) Cs2CuCl4 (TN = 0.6 K) in magnetic fields up to 18 T applied along the a axis. The possibility for a Bose-Einstein condensation of magnons in the AFM phase and a proximity to the spin liquid state at low temperatures beyond the AFM phase has been suggested for this compound. The longitudinal acoustic c11 mode shows pronounced anomalies in sound velocity and sound attenuation at low temperatures and in applied magnetic field. Below 1.5 K, this mode demonstrates a softening with increasing field, followed by an increase of the sound velocity close to the saturation field, Bs approx 8.5 T. The ultrasonic results are analyzed with a theory based on exchange-striction coupling. There is good qualitative agreement between theoretical results and experiment.

  • Poster
    ICM 09 (International Conference on Magnetism), 26.-31.07.2009, Karlsruhe, Deutschland

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Publ.-Id: 13055