As-deposited high <i>T</i> <i>c</i> and <i>J</i> <i>c</i> superconducting thin films made at low temperatures

2000 Å as-deposited high Tc superconducting Y1Ba2Cu3O7−x films with zero-resistance temperatures of ∼89 K and critical current densities about 0.7×106 A/cm2 at 77 K have been reproducibly fabricated at a substrate holder temperature of 650 °C, using pulsed laser deposition, with no post-annealing. One key to these results is the injection of gaseous oxygen into the laser-produced plume just in front of the target. In this way, the correct amount of oxygen is incorporated into the as-grown film so that post-deposition treatment becomes unnecessary. The in situ growth of such high Tc and Jc films is an important step in the use of the laser deposition technique to fabricate multilayer structures such as Josephson junctions.