Comment on "Field-enhanced diamagnetism in the pseudogap state of the cuprate Bi(2)Sr(2)CaCu(2)O(8+delta) superconductor in an intense magnetic field".

In a recent Letter[1], Wang et al. claim that “the magnetization results above TC distinguish M from conventional amplitude fluctuations and strongly support the vortex scenario for the loss of phase coherence at TC .” However, we will present here some examples for T > TC that show that the data of Ref.[1] may be explained on the grounds of the conventional Ginzburg-Landau (GL) scenario. We have checked that this conclusion applies also to both the temperature and the magnetic field dependende of M below TC . Note first that the absence on non-local electrodynamic effects on the fluctuation magnetization M ′ measured in Ref.[1] just confirms earlier results (see, e.g., Refs.[2, 3]). A similar absence was also observed in dirty low-TC superconductors[4] and therefore, contrary to the claims of Wang et al., it does not provide a “first evidence” of unconventional fluctuations. To estimate M (T,H) above but not too close to TC we may use the GL theory with Gaussian fluctuations (GGL approach) in the 2D limit[5],