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Anomaly in YBa2Cu4O8 charge distribution below Tc: a zero-field muSR study

P. Carretta·A. Keren·J. S. Lord·I. Zucca·S. M. Kazakov·J. Karpinski
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Abstract

Zero-field $μ$SR measurements in $^{63}$Cu isotope enriched and natural YBa$_2$Cu$_4$O$_8$ powders are presented. The temperature dependence of the $μ^+$ relaxation rate is characterized by a sizeable enhancement below T$_c$. The comparison of the asymmetry decay in the two samples reveals that the $μ^+$ relaxation is driven by nuclear dipole interaction from 300 K down to 4.2 K. It is argued that the increase in the relaxation below T$_c$ originates from a change in $μ^+$ site, possibly due to a modification in the charge distribution within CuO chains.

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P. Carretta, A. Keren, J. S. Lord, I. Zucca, S. M. Kazakov, J. Karpinski. 2004-07-19. Anomaly in YBa2Cu4O8 charge distribution below Tc: a zero-field muSR study. https://doi.org/10.1103/physrevb.71.052507

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