Fluctuation-induced diamagnetism in biperiodic layered superconductors in the weak magnetic field regime

Fluctuation-induced in-plane conductivity, magnetoconductivity, and diamagnetism ofBi2Sr2Pomar1, Ramallo2, Mosqueira3 et al. 1996Phys. Rev. BSelf Cite563380View full textAdd to dashboardCite

“…Taking into account that in Bi-2212 crystals ab ͑0͒Ϸ0.9 nm ͑see later͒, even for 0 Hϭ5 T one may expect deviations of the weak-magnetic field OPF behavior only for Շ10 Ϫ2 , which is less than the expected Ginzburg reduced temperature. 17 Note, finally, the striking differences between the ⌬ ab () H data for the two crystals studied here ͓compare the results for 0 Hϭ1T in Figs. 3͑a͒ and 3͑b͔͒.…”

“…In the case of the fluctuation-induced diamagnetism, we have presented already some results obtained in other Bi-2212 crystals. 16,17 However the interest of the new ⌬ ab data presented here is enhanced by the fact that they correspond to the crystals on which we have also measured the paraconductivity and the fluctuation-induced magnetoconductivity and, therefore, these data will allow a simultaneous, quantitative and consistent analysis of the three quantities, all of which depend on the same characteristic lengths. Two basic and new aspects of this analysis are ͑i͒ whereas the effective mean-field critical exponent, x, of the paraconductivity and of the fluctuation-induced diamagnetism is of the order of xϷϪ1, it is xϷϪ3 for the fluctuation-induced magnetoconductivity in the weak magnetic field limit.…”

“…͑ii͒ The analysis of the three quantities will be performed on the grounds of the theoretical approaches that take into account the presence of two CuO 2 layers in s, the periodicity length associated with these superconducting layers. 17,19,21,22,24,26 Together with the important corrections associated with the inhomogeneities, the influence of the two superconducting layers in s will be crucial to explain simultaneously and consistently both the reduced temperature behavior and the amplitude of the three quantities studied here.…”

Reply to “Comment on ‘Diamagnetism and Cooper pairing aboveTcin cuprates' ”

“…The juxtaposition of an extremely large pairing energy scale (d-wave gap amplitude ∆ ∼40 mV) and a weak c-axis phase stiffness leads to this very unusual phase locking-unlocking scenario which seems pervasive in the hole-doped cuprates. We argue that this situation cannot be treated by applying the mean-field GL approach 1 to the Lawrence-Doniach (LD) Hamiltonian 8,9 .…”

“…6 the plots of χ vs. T at selected values of H. Above T c , all values of χ below 2 T collapse to a single curve, which defines the linear-response fluctuation susceptibility that can be directly compared with mean-field theories 1,8,9 . For illustration, we show as a dashed curve the best fit to the linear-response MF expression 8…”