On the estimate of the spin-gap in quasi-1D Heisenberg antiferromagnets from nuclear spin-lattice relaxation

1999/04/06 by R. Melzi, Melzi, R., P. Carretta +1
Physics and Astronomy · #FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.str-el

paper · pdf · doi:10.48550/arxiv.cond-mat/9904074

4 pages, 3 figures, Proc. of the Stripes 98 Conference (Roma, June 1998)

arxiv created 1999/04/06 · arxiv updated 2009/11/30

Abstract

We present a careful analysis of the temperature dependence of the nuclear spin-lattice relaxation rate 1/T₁ in gapped quasi-1D Heisenberg antiferromagnets. It is found that in order to estimate the value of the gap correctly from 1/T₁ the peculiar features of the dispersion curve for the triplet excitations must be taken into account. The temperature dependence of 1/T₁ due to two-magnon processes, is reported for different values of the ratio r=J_⊥/J_∥ between the superexchange constants in a 2-leg-ladder. As an illustrative example we compare our results to the experimental findings for ⁶³Cu 1/T₁ in the dimerized chains and 2-leg-ladders contained in Sr₁₄Cu₂₄O₄₁

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