Correlations, spin dynamics, defects: the highly-frustrated Kagomé bilayer
Тема:
К семидесятилетию антиферромагнетизма
Інший ID:
PACS: 75.40.Gb, 75.50.Lk, 76.75.+i, 76.60.–k
Посилання:
Correlations, spin dynamics, defects: the highly-frustrated Kagomé bilayer / D. Bono, L. Limot, P. Mendels, G. Collin, N. Blanchard // Физика низких температур. — 2005. — Т. 31, № 8-9. — С. 929-951. — Бібліогр.: 92 назв. — англ.
Підтримка:
We thank H. Alloul, F. Bert, J. Bobroff, R.J.
Cava, D. Huber, A. Keren, C. Lhuillier, M. Mekata,
G. Misguich, R. Moessner, C. Mondelli, H. Mutka,
B. Ouladdiaf, C. Payen, P. Schiffer and P. Sindzingre
for fruitful discussions. We also wish to thank
A. Amato, C. Baines and A.D. Hillier, our SR local
contacts, whose outstanding efforts have made these
experiments possible.
The SR experiments were performed at the Swiss
Muon Source, Paul Scherer Institute, Villigen, Switzerland,
and financially supported by the Federal Office
for Education and Science, Berne, Switzerland, as
well as at the ISIS facility, Rutherford Appleton Laboratory,
Didcot, United Kingdom.
Part of this work was financially supported by the
EC IHP Programme for large scale facilities and by
the EC Framework Programmes V and VI.
We are grateful to the muon beamline groups and
to the technical staff of Laboratoire de Physique des
Solides, Orsay.
Дата:
2005
Переглядів:
624
Завантажень:
453
Анотація:
The SrCr₉p Ga₁₂-₉pO₁₉ and 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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