Superconducting YBa2Cu3O7thin films have been prepared by using a magnetron sputtering system in the single‐source mode. Samples deposited on [100] single‐crystal MgO with and without a Au buffer layer all show high transition temperatures (82–87 K). The use of a Au buffer layer significantly improves the superconducting properties, particularly the Meissner effect and critical current density (3.3×106A/cm2atT=2 K and 3.5×104A/cm2atT=77 K). The Au films remain metallic after high‐temperature annealing in an oxygen atmosphere. We propose to use Au buffer layers as current shunts to protect superconducting films and devices.