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Muon-spin relaxation measurements on the dimerized spin-1/2 chains NaTiSi2O6 and TiOCl

P. J. Baker·S. J. Blundell·F. L. Pratt·T. Lancaster·M. L. Brooks·W. Hayes·M. Isobe·Y. Ueda·M. Hoinkis·M. Sing·M. Klemm·S. Horn·R. Claessen
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Abstract

We report muon spin relaxation (muSR) and magnetic susceptibility investigations of two Ti3+ chain compounds which each exhibit a spin gap at low temperature, NaTiSi2O6 and TiOCl. From these we conclude that the spin gap in NaTiSi2O6 is temperature independent, with a value of 2*Delta=660(50)K, arising from orbital ordering at Too = 210K; the associated structural fluctuations activate the muon spin relaxation rate up to temperatures above 270K. In TiOCl we find thermally activated spin fluctuations corresponding to a spin gap 2*Delta=420(40)K below Tc1=67K. We also compare the methods used to extract the spin gap and the concentration of free spins within the samples from muSR and magnetic susceptibility data.

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P. J. Baker, S. J. Blundell, F. L. Pratt, T. Lancaster, M. L. Brooks, W. Hayes, M. Isobe, Y. Ueda, M. Hoinkis, M. Sing, M. Klemm, S. Horn, R. Claessen. 2006-10-10. Muon-spin relaxation measurements on the dimerized spin-1/2 chains NaTiSi2O6 and TiOCl. https://doi.org/10.1103/physrevb.75.094404

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