Superconducting Fluctuations Above the Critical Temperature in Bi2Sr2Ca1−xYxCu2O8+δ as Revealed by Microwave Absorption

Abstract

The superconducting fluctuations above the critical temperature in Bi₂Sr₂Ca_1−xY_xCu₂O_8+δ (x = 0–0.3) single crystals are studied by microwave absorption (MWA). The maximum in the MWA temperature dependence was observed close to the critical temperature. Its formation is explained by the change of the quasiparticle density of states due to superconducting fluctuations. The fluctuation area boundary is plotted on the phase diagram using the variation of the MWA temperature dependence with the hole density and is compared with the pseudogap phase behavior.