Speaker
Description
We have fabricated Gd123 thin films co-doped with several kinds of RE₂CuO₄ (RE214: RE = Gd, Nd, Sm, Eu) by the FF-MOD method and investigated their superconducting properties. We have already reported that the introduction of the superconductor RE214 (Tc = 18.5 K) as an artificial pinning center (APC) into RE123 thin films which improved the Jc-B properties for the first time [1]. In this study, we introduced multiple types of RE214 with different lattice constants into the base Gd123 material for finer RE214 crystals and attempted to further improve the Jc-B properties. As a result, with the same volume fraction of RE214 introduced, the Jc-B properties improved as the number of different types of RE214 co-doped increased, and all films showed better Jc-B performance compared to non-doped films. At 4.2 K and 6.9 T parallel to the c-axis of Gd123 thin films, the Jc was 0.782 MA/cm² with the addition of Sm214 and 0.877 MA/cm² with the addition of three types (Gd214, Nd214, Sm214), representing increases of 1.07 times and 1.19 times, respectively, compared to the non-doped film. TEM images also confirmed that the RE214 pins were oriented along the c-axis, and it is inferred that they are introduced in a plate-like manner within the ab-plane. Therefore, it is expected that applying a magnetic field perpendicular to the c-axis during magnetization measurements could result in even higher calculated Jc values.
Moving forward, further improvements in superconducting properties are expected by altering the combinations of RE in RE214, their doping ratios, and the sintering conditions.
References
[1] R.Ishii, O.Miura,” Achievement of high critical current densities by co-doping BaMO3 (M= Zr, Ce, Sn) and Gd2CuO4 for FF-MOD GdBa2Cu3O7-σ thin films”, The Applied Superconductivity Conference2024, Utah(U.S.A), September 2024.
