Lanthanum gallate substrates for epitaxial high-temperature superconducting thin films

Abstract

We demonstrate that lanthanum gallate (LaGaO3) has considerable potential as an electronic substrate material for high-temperature superconducting films. It provides a good lattice and thermal expansion match to YBa2Cu3O7−x, can be grown in large crystal sizes, is compatible with high-temperature film processing, and has a reasonably low dielectric constant (ε≂25) and low dielectric losses. Epitaxial YBa2Cu3O7−x films grown on LaGaO3 single-crystal substrates by three techniques have zero resistance between 87 and 91 K.