Preparation of High-Quality Conductive La 0.7 Sr 0.3 MnO 3 Buffer Layer Applied to Low-Cost YBCO-Coated Conductors

Abstract

Through a simple and low-cost way to gain the precursor solution, a conductive and high-quality La_0.7Sr_0.3MnO₃ (LSMO) buffer layer approximately 280 nm thick only by one single coating was successfully deposited on LaAlO₃ (LAO) (100) single crystal substrates using an independently developed new method of polymer-assisted chemical solution deposition (PA-CSD). Highly epitaxial YBa₂Cu₃O_7−x (YBCO) superconducting film with thickness of 500 nm managed to be deposited on LSMO/LAO. A study was made on the LSMO buffers and YBCO films with XRD, SEM, and superconducting critical temperature (T_c) analyses. The temperature-dependent resistivities of YBCO on insulating BaZrO₃ (BZO) buffer layer and on conductive LSMO buffer layer were also investigated. It was found that the conductive LSMO buffer prepared at 840 °C in argon would possess high-degree out-of-plane and in-plane texturing, good density with a sufficient thickness about 280 nm, and microcrack-free nature. More importantly, the value of the self-field critical current density (J_c) of YBCO superconducting film on LSMO/LAO architecture was 2.8 MA/cm² at 77 K.