Diamagnetic transition of Bi2223/Ag tapes: the role of low-number stacks of superconducting layers

摘要

A new interpretation of the diamagnetic transition in Bi2223/Ag tapes is proposed. The main distinction from the previous models is the proper treatment of the role of low-number stacks of unit-cells. The new arguments to the existence of these stacks are given. The onset temperature of the real AC susceptibility chi' is interpreted as the melting temperature of the thickest stack. The middle temperature of chi'(T) transition and the peak temperature of the imaginary part define the melting temperature of dominant stacks. The pinning and the critical current behavior are re-analyzed in connection with the appearance of low-number stacks and the suppression of interstack Josephson interaction. (C) 1998 Elsevier Science B.V. [References: 28]