It is shown that the magnetization rounding measured by L. Li and coworkers above the superconducting transition in optimally doped YBa2Cu3O7-d crystals under magnetic fields up to 14 T [Phys. Rev. B 81, 054510 (2010), arXiv:0906.1823] may be explained at a phenomenological level in terms of the mean field Gaussian-Ginzburg-Landau (GGL) approach for layered superconductors. This result challenges the claims of L. Li and coworkers, who write '[...] we are observing the phase-disordering mechanism, rather than Gaussian mean-field fluctuations', but it is in full agreement with earlier magnetization measurements by different authors in optimally-doped YBa2Cu3O7-d under lower magnetic fields. The adequacy of the mean-field Ginzburg-Landau descriptions is further confirmed when analyzing in terms of the GL scaling in the lowest-Landau-level (GL-LLL) approximation the magnetization data reported below Tc by L. Li and coworkers.
@article{arxiv.1212.2809,
title = {Comment on 'Diamagnetism and Cooper pairing above Tc in cuprates'},
author = {R. I. Rey and A. Ramos-Álvarez and J. Mosqueira and M. V. Ramallo and F. Vidal},
journal= {arXiv preprint arXiv:1212.2809},
year = {2013}
}