Multiparticle continuum in the excitation spectrum of the compound CsNiCl |
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Authors: | E. Ercolessi G. Morandi M. Roncaglia |
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Affiliation: | (1) Physics Department, University of Bologna, INFM and INFN, 6/2 v.le B. Pichat, 40127, Bologna, Italy, IT |
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Abstract: | Recent neutron scattering experiments on CsNiCl3 reveal some features that are not well described by the standard nonlinear σ model, nor by numerical simulations, for isolated S = 1 spin chains. In particular, in real systems at the antiferromagnetic point of the Brillouin zone, the intensity of the continuum of multiparticle excitations, at T = 6 K, is about 5 times greater than predicted. Also, the spin gap is higher and the correlation length is smaller than predicted. We propose a theoretical scenario where the interchain interaction is approximated by an effective staggered magnetic field, and that yields a correct prediction for the observed quantities. Received 2 October 2002 / Received in final form 19 March 2003 Published online 7 May 2003 |
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Keywords: | PACS. 75.10.Jm Quantized spin models – 75.50.-y Studies of specific magnetic materials |
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