Drift velocity and temporal phase fluctuations of sliding charge density waves in Rb0.3MoO3Reportar como inadecuado




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Abstract : The dynamics of CDW-s depinned by an electric field is investigated by transport, voltage noise and NMR measurements on a Rb0.3MoO 3 single crystal. A direct measurement of the bulk winding rate ν d of the sliding CDW phase is provided by the observation of sidebands in the motionally narrowed NMR spectra and by the oscillations of the spin echo amplitude as a function of the delay time. Comparison with the noise spectra confirms our earlier statement that νd is equal to the voltage noise frequency νn with an accuracy of 10 %. Experimental NMR spectra at a field of E-ET ~ 20 ET is the depinning threshold in the temperature range of 40 to 60 K have been fitted with high accuracy to lineshapes calculated under the assumption that the noise spectrum is related to the spatial current distribution in a simple way. Most of the experiments can be interpreted by considering the crystal as a collection of domains. In each domain the current is coherent for long times, we found in some cases a temporal coherence of 25-50 oscillation periods of the hyperfine field. We discuss stochastic variations of the CDW phase which become important at high temperatures, especially at fields near threshold.

Keywords : charge density waves fluctuations NMR line breadth random noise rubidium compounds spin echo NMR





Autor: P. Butaud P. Ségransan A. Jánossy C. Berthier

Fuente: https://hal.archives-ouvertes.fr/



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