Line-beam scan irradiation for preparation of YBCO films with high-Jc by excimer-laser-assisted MOD (ELAMOD)

Preparation of epitaxial YBa2Cu3O7 (YBCO) films on cerium oxide-buffered sapphire (r-cut α-Al2O3) substrates by an excimer-laser-assisted metalorganic deposition (ELAMOD) is reported. The ELAMOD process has been developed to bring about the advantage of shorter heating time than that in the conventional metalorganic deposition; the coated films are irradiated by an excimer laser beam before firing. We initiated the ELAMOD-YBCO process using a homogenized 8-mm-square laser beam which irradiates the coated surface in a fixed substrate mode. In order to extend the process applicable to large-area films, a scan irradiation mode was employed and a high critical-current density over 6 MA/cm2 has been observed. In the process, an appropriate choice of laser energy is difficult but crucial to obtain YBCO films with high superconducting properties. Then, laser irradiation from backside of the substrate was examined and proved to be beneficial to extend the experimental window of the laser energy. Moreover, a newly developed ELAMOD process using a 90-mm-wide line-beam is also reported which has a potential ability for large-area applications.