Low-temperature preparation of superconducting YBa2Cu3O7−δ films on Si, MgO, and SrTiO3 by thermal coevaporation

Abstract

We used simple thermal coevaporation of yttrium, barium, and copper in an oxygen atmosphere to produce thin films of the 90 K superconductor, YBa₂Cu₃O_7−δ, on silicon, magnesium oxide, and strontium titanate. The films were deposited on 650 °C substrates and were superconducting when removed from the evaporator. A short post‐anneal at 480 °C produced films on bare Si with transition temperatures (R=0) of 85 K. Films as thin as 0.13 μm, superconducting at 91 K (on MgO) and 89 K (on SrTiO₃), were obtained with no post‐anneal.