Superconducting YBa2Cu3O7 thin films have been prepared by using a magnetron sputtering system in the single‐source mode. Samples deposited on  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 (3.3×106 A/cm2 at T=2 K and 3.5×104 A/cm2 at T=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.