Aging of superconducting Y1Ba2Cu3O7−x structures on silicon

Abstract
The long‐term stability of epitaxial thin film structures of superconducting Y1Ba2Cu3O7−x on silicon wafers (100), using a yttria‐stabilized ZrO2(YSZ) buffer, is presented and compared to identical structures on SrTiO3 (100) and yttria‐stabilized ZrO2 (100) single crystals. For Y1Ba2Cu3O7−y/YSZ/Si heterostructures, the maximum Y1Ba2Cu3O7−y film thickness is limited to 50 nm; otherwise thermal strain induces microcracks. Thinner films are more stable, but nevertheless show aging over several weeks, which affects critical current density and room‐temperature resistivity, but not the critical temperature Tc.