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Magnon dispersion and thermodynamics in CsNiF_3

J. Karadamoglou·N. Papanicolaou·X. Wang·X. Zotos
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Abstract

We present an accurate transfer matrix renormalization group calculation of the thermodynamics in a quantum spin-1 planar ferromagnetic chain. We also calculate the field dependence of the magnon gap and confirm the accuracy of the magnon dispersion derived earlier through an 1/n expansion. We are thus able to examine the validity of a number of previous calculations and further analyze a wide range of experiments on CsNiF_3 concerning the magnon dispersion, magnetization, susceptibility, and specific heat. Although it is not possible to account for all data with a single set of parameters, the overall qualitative agreement is good and the remaining discrepancies may reflect departure from ideal quasi-one-dimensional model behavior. Finally, we present some indirect evidence to the effect that the popular interpretation of the excess specific heat in terms of sine-Gordon solitons may not be appropriate.

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J. Karadamoglou, N. Papanicolaou, X. Wang, X. Zotos. 2000-11-29. Magnon dispersion and thermodynamics in CsNiF_3. https://doi.org/10.1103/physrevb.63.224406

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