Measurement of fluctuation-induced diamagnetism in BSCCO-2212 single crystals using magneto-optics

Fluctuation-induced diamagnetism in BSCCO single crystals with different doping levels (i.e., different oxygen stoichiometry) was measured using magneto-optics (MO) in a wide frequency range up to several MHz. A shift in Tc onset, measured by MO, of up to 6 K towards higher temperatures was observed at high frequencies in those samples which are far from the optimally doped condition. An explanation of the observed effect in terms of the phase fluctuations of the superconducting order parameter is proposed.