The unparalleled loss-less electrical current conduction of high-temperature superconducting (HTS) materials encourages research on materials like YBa₂Cu₃O_7−𝛿 (YBCO) to unravel opportunities towards numerous applications. Nonetheless, production costs and throughput of the commercialized HTS Coated Conductors (CCs) are still limiting a worldwide spread of these materials. Transient liquid assisted growth (TLAG) is a non-equilibrium process created at ICMAB displaying ultrafast growth rate which, when combined with chemical solution deposition (CSD), is emerging as a strong candidate to reduce the cost/performance ratio of YBCO superconductors.

The work now published in Advanced Materials shows the critical role played by the composition of the transient liquid, especially of the Barium and Copper (Ba:Cu) ratio of the Ba-Cu-O oxide, on the nucleation and growth of the epitaxial superconducting YBCO films. The advanced in situ characterization of the growth process using synchrotron X-ray diffraction and coupled to multiparameter nanostructural (Transmission Electron Microscopy) and physical performance investigations has been key to reach high-performance YBCO films. The high-throughput fabrication of YBCO conductors using TLAG will promote the use of HTS materials in large scale power applications such as fusion reactors.

A collaborative research

The story of the research performed as a collaboration among ICMAB and ALBA Synchrotron arises from the creation of the “Energy Transition Joint Lab at ALBA” funded by ALBA and CSIC within the scope of the Interdisciplinary Technology Platform PTI+ Trans-Ener. The initial experiments were performed at SOLEIL synchrotron near Paris (France) and then a new more complete platform was installed at ALBA allowing to use it in several beamlines, such as NCD-SWEET or CLAESS. This platform has become a unique facility being used by users from worldwide to analyze in situ growth and phase transformation processes under variable temperatures and oxygen pressures with very fast acquisition times. The platform is a correlative experience because, in addition to synchrotron radiation data, the system performs simultaneously electrical conductivity measurements and mass spectroscopy analyses of exhaust gases.

The established collaboration is completed with inputs form researchers of the University of Girona and the use of JEMCA transmission electron microscopy facilities. The present article is a first example of the powerful capabilities of this new platform which is now being used to perform systematic analyses of many different high temperature superconducting materials.