Observation of a linear regime in imaginary χ < inf > ac < /inf > of Bi-2223 superconductor

Abstract

Measurements of complex AC susceptibility were performed on Bi-2223/Bi-2212 high Tc superconductor at low excitation field amplitudes. Unusual features attributable to the Bi-2223 phase are observed in the imaginary part of the AC susceptibility, χ″(T), at different excitation field amplitudes, Hm. The peak temperature, Tp as a function of Hm defines a region in (H, T) plane, where χ″ is independent of Hm. Various possible interpretations are discussed, including that of a transition to a viscous flux flow regime. © World Scientific Publishing Company.