Improvement of Surface Morphology and Critical Current Density of YDy0.2Ba2Cu3.3O7−δ Thick Films by Inserted RE2O3 Thin Films

Various artificial multilayers consisting of YDy0.2 Ba2Cu3O7−ε/RE2O3/YDy0.2Ba2Cu3O7−ε films (RE = Y, Gd, Eu, etc.) about 1 μm in a sandwich-type structure are fabricated on oxide-buffered Hastelloy substrates using low-fluorine metalorganic deposition (MOD) method. Superconducting and microscopic performances are studied on composite YDyBaCuO multilayer films with and without intercalated Y2O3, Gd2O3, and Eu2O3 ultrathin films. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) are used to investigate growth orientation and surface morphology, revealing that multiple superconducting YDyBaCuO thin films separated by an ultrathin RE2O3 interlayer have better c-axis orientation, better in-plane and out-plane textures, as well as superior surface morphology. Using this interlayer technology, a significant enhancement of critical current density (Jc) both in self-field and under applied magnetic field is obtained.