Layer-by-layer deposition of La sub 1. 85 Sr sub 0. 15 CuO sub x films by pulsed laser ablation

Reflection high-energy electron diffraction (RHEED) has been used to monitor the growth of La{sub 1.85}Sr{sub 0.15}CuO{sub {ital x}} (LSCO) thin films on (100) SrTiO{sub 3} substrates by pulsed laser deposition. The films are grown using a combination of pulsed molecular oxygen and a continuous source of atomic oxygen, with the average background pressure maintained as low as 1 mTorr. The RHEED pattern is sharp and streaky, and the intensity of the specular beam oscillates during the deposition, indicating a two-dimensional layer-by-layer epitaxial growth. The film thickness measured by x-ray small-angle interference is consistent with the thickness determined by the RHEED oscillation period with a growth unit of half a unit cell. Thin films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) with good RHEED oscillations have also been grown under similar oxygenation conditions. The low-pressure-grown LSCO and YBCO films are superconducting, with zero-resistance temperatures of 15 and 80 K, respectively.