Speaker
Description
We present progress in development and understanding of the in-field performance of REBCO conductor with Artificial Pinning Centers (APCs) in the form of BMO nanorods (M = Zr, Hf, Sn, etc.). First, we present TEM findings on in-plane strain accommodation mechanisms between BMO and REBCO matrix, where the interfaces have been found to never be fully coherent, and that the degree of semi-coherency drives the equilibrium nanorod diameter, which is found to assume discrete values. Second, we present findings on the in-field performance as a function of operating field and temperature (B, T) and the degree of correlation between different operating regimes. We address the high level of statistical fluctuations of in-field performance found in both production and research conductors and analyze the features behind pairs of Jc(B1, T1) and Jc(B2,T2) that show high level of correlation. Third, we present results on the feasibility of using indirect, non-destructive characterization methods to predict Jc(B, T) performance over a wide range of fields and temperatures, as high temperature performance (65-77 K) is found to be poorly correlated to low-temperature (4.2 – 40 K), intermediate-to-high field (~3-30 T) performance of interest for applications. We present an in-depth study of scanning Raman spectroscopy and 2D-XRD features and their effect on the resulting in-field performance over 4.2-77 K and measured fields of 0-14 T. The main identified features that correlate to in-field performance are analyzed both in terms of level of correlation and in terms of the underlying microstructural features.
This work was funded by award DE-SC0016220 from the U.S. Department of Energy, Office of Science – High Energy Physics and award DE-AR0001374 from Advanced Research Projects Agency – Energy.
