Fabrication of superconducting YBa2Cu3O7−x delay lines by a chemically modified sol-gel method

Utilizing the photosensitivity of YBa2Cu3O7−x (YBCO) gel films, superconducting YBCO delay lines were fabricated on 1 in. LaAlO3 (LAO) single crystalline substrates by a chemically modified sol-gel process. Laser confocal scanning microscopy (LCSM) and X-ray diffraction (XRD) analyses of the prepared YBCO delay lines revealed a well-defined structure and a strong c-axis orientation. The superconductivity and delay properties were measured using a low-temperature superconducting tester and network analyzer, showing that the resulting delay lines have excellent superconductivity properties with a high critical transition temperature (Tc) of 91 K, a transition width (ΔT ) of 1.2 K and a critical current density (Jc) of 1.4×106 A/cm2 at 78 K, and the superconductivity properties were not affected by using the novel chemically modified sol-gel method. The measured delay time of the delay line was about 8.6 ns.