A new ac technique for fast and continuous characterization of coated conductor tapes

Abstract

A new ac technique for high-speed characterization of long coated conductor tapes is proposed and demonstrated. The technique utilizes an excitation coil and a small pick-up coil and continuously measures the ac susceptibility of a traveling superconducting tape. The pick-up coil signal is phase-sensitively detected by a digital lock-in amplifier and the ratio between the real and imaginary components is converted into the critical current density of the superconducting tape relying on a simple critical state assumption. An advantage of the technique is that precise information about the size and the location of coils is not necessary because the ratio is not sensitive to them. The technique is also useful for the characterization of striated tapes, for which the conventional Hall sensor array technique does not give useful information.

AC susceptibility as a characterization tool for coated conductor tapes

“…Strong correlation between the critical currents determined in two ways is obvious and a systematic deviation in the absolute values could be attributed to the difference in electric field, which in the AC experiment is about 100 times higher. AC susceptibility can therefore also be used for a reel-to-reel quality testing of CC tapes [81,82].…”

Microstructure and texture evolution of CeO2 buffer layers fabricated via CSD method in reducing atmosphere with different flow rates

“…The second generation high temperature superconducting (HTSC) coated conductors composed of metal substrate/ buffer layer/superconducting layer/protective layer are the most promising materials because of its possible engineering application in magnetic field [1][2][3][4]. Orientation growth of the buffer layer is of great important because it determined the texture and microstructure of subsequent superconducting film, which in turn is strongly related to the performance of coated conductors tape [5,6].…”