Investigation of the Meissner transition in bulk Bi-2212 in an AC magnetic field

Abstract

The frequency and applied field dependence of AC magnetic susceptibility of Bi-2212 is investigated. Frequency and magnetic field was varied from 800 Hz to 8 kHz and 0.097 mT to 1.84 mT respectively. Results show that the in-phase traces exhibit a sharp single transition at 800 Hz with varying fields. Analysis of the behavior of the peak in the out-of-phase signal shows that the hump in the real part of susceptibility is a simple projection of the intergranular loss peak. This hump starts to appear with increasing frequency. Further arguments disproving a double Meissner transition are presented.