Inspection of fabrication defects in REBCO coated conductors from various industrial manufacturers under similar fabrication conditions using the DEM approach

Abstract

In this study, the authors carried out an inspection of the extent of fabrication defects in rare-earth barium copper oxide (REBCO) coated conductors (CC) using the displacement-energy model (DEM) approach. The DEM approach can simulate the creation, propagation, and distribution of interfacial defects during the deposition of films onto a substrate, thereby save researchers the enormous resources needed to carry out similar studies experimentally. Defects in a sample originate from the interlayer interactions such as the thermal mismatch and eigenstates of layers as a function of temperature and time, respectively. The induced strains or gaps (determined by an increase in a lattice constant) between an interface in a sample caused by the interlayer interactions are computed as losses of bonding energy between interacting molecules using modified Hamaker models. The samples used for the simulation are based on the tape architecture of three leading industrial manufacturers of coated conductors (SuperPower Incorporated, Bruker High-Temperature Superconductors, and American superconductors). Also, in the simulation of this study, it assumes the samples from the manufacturers have a similar size (length x width) and fabrication method (chemical deposition method) to determine a tape architecture with comparatively lesser fabrication defects under similar fabrication conditions. Primarily, simulation results show that samples with more number of layers suffer relatively higher losses of bonding energy. According to this study and previous studies, the computed results on the DEM approach are consistent with those on several valuable experiments and models in the literature.