In situ preparation of the Gd-Ba-Cu-O superconducting thin films on (100) LaAlO3 by sputtering

High-temperature superconductor GdBa2Cu3O7 thin films were grown in situ on LaAlO3 single-crystal substrates by dc magnetron sputtering using a single planar target. 93% samples had a zero resistance transition temperature Tc0 more than 90 K and a transition width less than 1 K. The best films had a Tc0 of 92.5 K, a transition width of 0.57 K, and a critical current density of 3.6×106 A/cm2 at 77 K. The reproducibility is very good. X-ray diffraction analysis showed c axis normal to the film’s surface.