Flux Pinning Properties in Y₂BaCuO₅-Doped YBa₂Cu₃Oy Films Fabricated with Vapor-Liquid-Solid Growth Method

High-temperature superconducting REBa2Cu3Oy (RE: Rare earth elements, REBCO) films need both a high-speed film fabrication with a well-oriented crystalline texture and an introduction of artificial pinning centers (APCs) to improve critical current densities Jcs in magnetic fields．A vapor-liquid-solid (VLS) growth method enables the REBCO films to grow rapidly with a high quality but makes it difficult to introduce the APCs．In this study, Y2BaCuO5 (Y211) was doped into YBa2Cu3Oy (Y123) films fabricated via the VLS method with a liquid layer of Ba3Cu7O10．A microstructure analysis revealed that nano-particle APCs with diameter less than 10 nm were successfully introduced into the YBCO films．The Y211-doped Y123 films show the highest critical temperature Tc and the Jc in magnetic fields with a chemical composition ratio close to the stoichiometry of Y123.