The Frequency Dependence of AC Susceptibility for Bi-2223/Ag Tapes With Varying Lengths

An experimental investigation on ac susceptibility χ = χ' - jχ'' of Bi-2223/Ag superconducting tapes with different lengths L is carried out under a perpendicular ac magnetic field. A series of n-value is deduced from the ac susceptibility scaling law, which is used to systematically analyze the induced current in Bi-2223/Ag superconducting tapes. Based on the experiment results, a critical length Lc is defined for the tapes as ten times the width of them. AC susceptibility χ shows conspicuous frequency dependence when the length L is smaller than L
_c
. This phenomenon is attributed to the induced transverse current in silver. In addition, the proportion of transverse current to total induced current increases with the decreasing length dimension in our research. The results help understand the electromagnetic properties of Bi-2223/Ag superconducting tapes better and lay down important experimental foundation for practical applications.