Thermal conductivity of REBCO tapes with different stabilizers from 4.2 to 200 K

TL;DR

This study measures and analyzes the thermal conductivity of REBCO tapes with different stabilizers across a temperature range of 4.2 to 200 K, highlighting the impact of stabilizer material and thickness on thermal performance.

Contribution

It provides detailed thermal conductivity data for REBCO tapes with Cu, Ag, and Ag-Au stabilizers, and correlates electrical and thermal properties to guide current lead design.

Findings

Cu stabilizer dominates thermal conduction in thin samples.

Ag-3at%Au stabilizer reduces thermal conductivity compared to silver.

REBCO with Ag-3at%Au stabilizer is suitable for current leads.

Abstract

REBCO coated conductor is a high temperature superconductor that has a wide range of applications, one of which is the current leads of magnet systems. In the design of current leads, it is crucial to minimize their thermal conduction while maintain stable electrical conduction. Therefore, thermal conductivity of various REBCO tapes need to be characterized and analyzed. In this research, we measured thermal conductivity of REBCO tapes in the longitudinal direction from 4.2 to 200 K. Samples with Cu, Ag and Ag-3at%Au stabilizers of various thicknesses were measured. The electrical conductivity of these stabilizers was also characterized by residual resistance ratio (RRR) measurements and correlated with the thermal conductivity results. We showed that in samples with 10 micron or less Cu stabilizer, thermal conduction is dominated by that of the Cu which has much higher thermal conductivity than the Hastelloy substrate and the superconductor layer. In addition, the sample with 3 micron Ag-3at%Au stabilizer has significantly lower thermal conductivity than that with 3 micron silver stabilizer. It is concluded that REBCO with Ag-3at%Au stabilizer is promising for current lead applications.