muSR study of the quantum dynamics in the frustrated S=3/2 kagomé bilayers.
We present muSR experiments in the S=3/2 kagomé bilayer compound Ba(2)Sn(2)ZnGa(10-7p)Cr(7p)O22 [BSZCGO(p)] and compare it to the isostructural SrCr(9p)Ga(12-9p)O19 [SCGO(p)], including for the latter new results for p > or =0.89. Quantum-dynamical low energy magnetic excitations are evidenced in this novel compound. We study the evolution of the muon relaxation rate with p, T, and field. A phenomenological model for the muon relaxation based on sporadic dynamics due to spin excitations in a singlet sea proposed by Uemura et al. is extended to all fields and T range. Its connection to the RVB picture is discussed, and we argue that such coherent states might mediate the interactions between "impurities" which induce the spin glass freezing.
Bono
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Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, 91405 Orsay, France.
Mendels
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P
Collin
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G
Blanchard
N
N
Bert
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F
Amato
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A
Baines
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C
Hillier
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