Epitaxial YBa2Cu3O<i>x</i> thin films on sapphire using a Y-stabilized ZrO2 buffer layer

Abstract

Epitaxial, c-oriented YBa2Cu3Ox thin films were deposited by dc sputtering on (11̄02)-sapphire substrates with an intermediate buffer layer of Y-stabilized ZrO2 (YSZ), which was grown by rf magnetron sputtering. The epitaxy of the YSZ and the YBa2Cu3Ox films was proved by Rutherford backscattering spectrometry combined with ion channeling. The YBa2Cu3Ox films exhibited transition temperatures of 90 K and had critical current densities exceeding 1.2×106 A/cm2 at 77 K in zero magnetic field.