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NMR evidence for a "generalized spin-Peierls transition" in the high magnetic field phase of the spin-ladder Cu2(C5N2H12)2Cl4

H. Mayaffre·M. Horvatic·C. Berthier·M. -H. Julien·P. Segransan·L. Levy·O. Piovesana
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Abstract

The magnetic field-induced 3D ordered phase of the two-leg spin-ladder Cu2(C5N2H12)2Cl4 has been probed through measurements of 1H NMR spectra and 1/T1 in the temperature range 70~mK - 1.2 K. The second order transition line Tc(H) has been determined between Hc1 = 7.52 T and Hc2 = 13 T and varies as (H-Hc1)^(2/3) close to Hc1. From the observation of anomalous shifts and a crossover in 1/T1 above Tc, the mechanism of the 3D transition is argued to be magnetoelastic, involving a displacement of the protons along the longitudinal exchange (J//) path.

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H. Mayaffre, M. Horvatic, C. Berthier, M. -H. Julien, P. Segransan, L. Levy, O. Piovesana. 2000-03-22. NMR evidence for a "generalized spin-Peierls transition" in the high magnetic field phase of the spin-ladder Cu2(C5N2H12)2Cl4. https://arxiv.org/abs/cond-mat/0003361

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