Correlations, spin dynamics, defects: the highly-frustrated Kagomé bilayer

Автор(и)

  • David Bono* Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, 91405 Orsay, France
  • Laurent Limot** Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, 91405 Orsay, France
  • Philippe Mendels Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, 91405 Orsay, France
  • Gaston Collin Laboratoire Léon Brillouin, CE Saclay, CEA-CNRS, 91191 Gif-sur-Yvette, France
  • Nicole Blanchard Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, 91405 Orsay, France

Ключові слова:

PACS: 75.40.Gb, 75.50.Lk, 76.75. i, 76.60.–k

Анотація

The SrCr9p Ga12-9pO19and Ba2Sn2 ZnGa10-7p Cr7pO22 compounds are two highly-frustrated magnets possessing a quasi-two-dimensional Kagomé bilayer of spin 3/2 chromium ions with antiferromagnetic interactions. Their magnetic susceptibility was measured by local nuclear magnetic resonance and nonlocal (SQUID) techniques, and their low-temperature spin dynamics by muon spin resonance. Consistent with the theoretical picture drawn for geometrically frustrated systems, the Kagomé bilayer is shown here to exhibit: (i) short range spin-spin correlations down to a temperature much lower than the Curie—Weiss temperature, no conventional long-range transition occurring; (ii) a Curie contribution to the susceptibility from paramagnetic defects generated by spin vacancies; (iii) low-temperature spin fluctuations, at least down to 30 mK, which are a trademark of a dynamical ground state. These properties point to a spin-liquid ground state, possibly built on resonating valence bonds with unconfined spinons as the magnetic excitations.

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Опубліковано

2005-08-03

Як цитувати

(1)
Bono*, D.; Limot**, L.; Mendels, P.; Collin, G.; Blanchard, N. Correlations, Spin Dynamics, Defects: the Highly-Frustrated Kagomé Bilayer. Fiz. Nizk. Temp. 2005, 31, 929-951.

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