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Quantum critical behavior induced by Mn impurity in CuGeO3

A. V. Semeno·N. E. Sluchanko·N. A. Samarin·A. A. Pronin·H. Ohta·S. Okubo·S. V. Demishev
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Abstract

Results of high frequency (60-315 GHz) studies of ESR in CuGeO3 single crystals containing 0.9% of Mn impurity are reported. Quantitative EPR line shape analysis allowed concluding that low temperature magnetic susceptibility for T <40 K diverges following power law with the critical exponent 0.81 and therefore manifests onset of a quantum critical (QC) regime. We argue that transition into Griffiths phase occurs at TG~40 K and disorder produced by Mn impurity in quantum spin chains of CuGeO3 may lead to co-existence of the QC regime and spin-Peierls dimerisation.

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A. V. Semeno, N. E. Sluchanko, N. A. Samarin, A. A. Pronin, H. Ohta, S. Okubo, S. V. Demishev. 2005-07-15. Quantum critical behavior induced by Mn impurity in CuGeO3. https://doi.org/10.1016/j.physb.2006.01.046

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