We studied the proximity effect in a series ofYBa2Cu2.7Fe0.3Oy/YBa2Cu3O7−&dgr;bilayer film with varyingYBa2Cu3O7−&dgr;thickness. In a bilayer of isolated YBCO islands, aTcof 72 K was observed, much higher thanTcof 32 K of theYBa2Cu2.7Fe0.3Oyfilm.TcandJcof thicker bilayers of continuousYBa2Cu3O7−&dgr;films were found to decrease with decreasing YBCO thickness. This behavior ofTcandJccan be explained by the Deutscher de Gennes theory for the proximity effect, provided one models the film as a series of grains whose lateral dimensions scale with the average film thickness. ©1998 American Institute of Physics.