Transient liquid assisted growth of superconducting YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7−x </sub> films based on pulsed laser deposition
Albert Queraltó, M. Sieger, Kapil Gupta, Alexander Meledin, Pedro Barusco, Lavinia Saltarelli, Mariona de Palau, X. Granados, X. Obradors, Teresa Puig
Abstract
Abstract We investigated the integration of transient liquid-assisted growth (TLAG) approach for epitaxial YBa 2 Cu 3 O 7− x (YBCO) films by physical deposition methodologies (pulsed laser deposition (PLD)), as an additional opportunity for high-throughput growth of YBCO. As a prerequisite, highly flat and amorphous YBCO precursor films were deposited by PLD at temperatures below 400 °C on single-crystalline SrTiO 3 (STO) and LaMnO 3 (LMO)/STO, as well as industrial coated conductor architectures. Contrary to TLAG based on chemical solution deposition, where BaCO 3 elimination is a key factor for the YBCO growth, TLAG-PLD growth is controlled by the transformation of Ba–Cu–O (s) to a transient liquid. High-quality c -axis YBCO films were successfully grown on different substrates, as demonstrated by high-resolution x-ray diffraction and transmission electron microscopy. In-situ resistance measurements revealed that the growth rates around 1000 nm s −1 can be achieved, outperforming the capabilities of standard PLD growth of REBa 2 Cu 3 O 7 films by few orders of magnitude. Experimental conditions such as temperature, oxygen partial pressure, and heating ramp, were optimized to obtain critical temperature ( T c ) values up to 90 K. Critical current densities of 15 MA cm −2 at 5 K and 1.7 MA cm −2 at 77 K were obtained for YBCO films of 450 nm on LMO/STO.