Data on the Tl205 NMR frequency shift and linewidth due to the magnetic field variation in the mixed state of Tl2Ba2Ca2Cu3O10+δ are presented. These data, which are commonly used to extract the London penetration depth, show a near linear temperature dependence at TTc. We offer an explanation of this effect as being caused by thermal fluctuations of vortices in weakly coupled layered systems. We argue that the fluctuations cannot be ignored in interpretation of NMR and Muon-Spin-resonance data for materials with large penetration depths even at low T.
ASJC Scopus subject areas
- Physics and Astronomy(all)