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Cu Nuclear Quadrupole Resonance Study of the Spin-Peierls Compound Cu1-xMgxGeO3: A Possibility of Precursory Dimerization

Y. Itoh·T. Machi·N. Koshizuka·T. Masuda·K. Uchinokura
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Abstract

We report on a zero-field 63Cu nuclear quadrupole resonance (NQR) study of nonmagnetic Mg impurity substituted Cu1-xMgxGeO3 (single crystals; the spin-Peierls transition temperature Tsp~14, 13.5, and 11 K for x=0, 0.0043, and 0.020) in a temperature range from 4.2 K to 250 K. We found that below T*~77 K, Cu NQR spectra are broadened and nonexponential Cu nuclear spin-lattice relaxation increases for undoped and more remarkably for Mg-doped samples. The results indicate that random lattice distortion and impurity-induced spins appear below T*, which we associate with a precursor of the spin-Peierls transition. Conventional magnetic critical slowing down does not appear down to 4.2 K below Tsp.

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Y. Itoh, T. Machi, N. Koshizuka, T. Masuda, K. Uchinokura. 2001-07-17. Cu Nuclear Quadrupole Resonance Study of the Spin-Peierls Compound Cu1-xMgxGeO3: A Possibility of Precursory Dimerization. https://doi.org/10.1103/physrevb.65.100406

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