Kinetic Control of Ultrafast Transient Liquid Assisted Growth of Solution-Derived YBa2Cu3O7-x Superconducting Films

Transient liquid assisted growth (TLAG) is an ultrafast non-equilibrium growth process mainly governed by kinetic parameters, which are only accessible through fast in situ characterizations. In situ synchrotron X-ray diffraction (XRD) analysis and in situ electrical resistivity measurements are used to derive kinetic diagrams of YBa2 Cu3 O7- x (YBCO) superconducting films prepared via TLAG and to reveal the unique peculiarities of the process. In particular, diagrams for the phase evolution and the YBCO growth rates have been built for the two TLAG routes. It is shown that TLAG transient liquids can be obtained upon the melting of two barium cuprate phases (and not just one), differentiated by their copper oxidation state. This knowledge serves as a guide to determine the processing conditions to reach high performance films at high growth rates. With proper control of these kinetic parameters, films with critical current densities of 2-2.6 MA cm-2 at 77 K and growth rates between 100-2000 nm s-1 are reached. These growth rates are 1.5-3 orders of magnitude higher than those of conventional methods.The authors acknowledge the European Research Council for the ULTRASUPERTAPE project (ERC-2014-ADG-669504), IMPACT project (ERC-2019-PoC-874964) and EU COST action for CA16218 (NANOCOHYBRI). The authors also acknowledge financial support from Spanish Ministry of Science and Innovation with PID2021-127297OB-C21 and PID2021-127297OB-C22, and from Spanish Ministry of Science, Innovation and Universities through the “Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2015-0496 and CEX2019-000917-S), and from the Spanish Ministry of Economy and Competitiveness with the SUMATE project (RTI2018-095853-B-C21, RTI2018-095853-B-C22, co-financed by the European Regional Development Fund, MCIU/AEI/FEDER, UE). They also thank the Catalan Government (2017-SGR-1519) and the Catalan energy network XRE4S (2018 XARDI 00002) for their support. L.S., D.G., and A.K. acknowledge financial support from Spanish Ministry of Science, Innovation and Universities through the FPI grant PRE2019-090621, PRE2018-084537, and PRE2020-091817, respectively. L.So. and J.J. acknowledge financial support from Spanish Ministry for the FPU grants. S.R. thanks the Universitat de Girona for IFUdG grant and A.Q. thanks the Spanish Ministry of Science, Innovation and Universities (“Juan de la Cierva” postdoctoral fellowship [Grant no. IJC2018-035034-I]). The authors thank the Scientific Services at ICMAB and ICN2 Electron Microscopy Division. The authors acknowledge the use of instrumentation as well as the technical advice provided by the National Facility ELECMI ICTS, node “Laboratorio de Microscopías Avanzadas” at University of Zaragoza. The authors also acknowledge SOLEIL Synchrotron for provision of synchrotron radiation facilities and are grateful for assistance while using the DiffAbs beamline.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe