High temperature superconductors for fusion applications and new developments for the HTS CroCo conductor design

Enhanced critical current density in optimized high-temperature superconducting bilayer thin films

The superconducting and structural properties of bilayer thin films based on YBa2Cu3O7-x / YBa2Cu3O7-x+6%BaZrO3heterstructures have been studied. In a broad range of magnetic field strengths and temperatures, the optimal bilayer film comprises 30% YBCO at the substrate interface and 70% YBCO+6%BZO on the top. The critical current density measured for the optimal bilayer structure is shown to outperform the corresponding single layer films up to almost 60%. The obtained results are comprehensively discussed in the light of our previously published theoretical framework (Rivastoet al2023J. Phys.: Condens. Matter35075701:1-10). We conclude that the bilayering provides an efficient and easily applicable way to further increase the performance and applicability of high-temperature superconductors in various applications. Consequently, the bilayer films should be seriously considered as candidates for the upcoming generation of coated conductors.

Defining inkjet printing conditions of superconducting cuprate films through machine learning

The design and optimization of new processing approaches for the development of rare earth cuprate (REBCO) high temperature superconductors is required to increase their cost-effective fabrication and promote market implementation. The exploration of a broad range of parameters enabled by these methods is the ideal scenario for a new set of high-throughput experimentation (HTE) and data-driven tools based on machine learning (ML) algorithms that are envisaged to speed up this optimization in a low-cost and efficient manner compatible with industrialization. In this work, we developed a data-driven methodology that allows us to analyze and optimize the inkjet printing (IJP) deposition process of REBCO precursor solutions. A dataset containing 231 samples was used to build ML models. Linear and tree-based (Random Forest, AdaBoost and Gradient Boosting) regression algorithms were compared, reaching performances above 87%. Model interpretation using Shapley Additive Explanations (SHAP) revealed the most important variables for each study. We could determine that to ensure homogeneous CSD films of 1 micron thickness without cracks after the pyrolysis, we need average drop volumes of 190-210 pl, and no. of drops between 5000 and 6000, delivering a total volume deposited close to 1 μl.