Interfilament Resistance at 77 K in Striated HTS Coated Conductors

TL;DR

This study investigates the transverse resistance in striated HTS coated conductors at 77 K to understand filament coupling paths, aiming to enhance AC loss reduction strategies.

Contribution

It provides a systematic analysis of transverse resistance in different HTS CC samples, revealing factors affecting filament coupling and suggesting improvements for striation techniques.

Findings

Transverse resistance varies with stabilizer presence and oxidation.

Coupling paths are influenced by filament and stabilizer properties.

Insights help optimize striation for better AC loss reduction.

Abstract

Striating HTS coated conductor (CC) tapes into narrow filaments offers the possibility of reducing the tapes' magnetization losses without unreasonably decreasing their current-carrying capability. However, realizing well-separated striations presents technological challenges, especially if the number of filaments is large and/or if a thick layer of metallic stabilizer is present. In these situations, the filaments can be easily coupled and their effectiveness to reduce magnetization losses is strongly diminished or eliminated. While the onset of coupling is well visible from magnetization loss measurements, the actual path of the coupling current is unknown. In this contribution we present a systematic study of the transverse resistance in HTS CC samples in order to get a deeper understanding of those paths. The measured samples differ in terms of manufacturer (SuperPower and SuperOx), and presence and thickness of stabilizer material. In addition, oxidation is used as a means to increase the resistance between the filaments in non-stabilized samples. The results are interpreted with a chain network model. This work provides useful insights on the factors determining the transverse resistance in striated HTS CCs, thus indicating ways to improve the effectiveness of the striation process for AC loss reduction.