Effect of interlayer magnetic coupling on the Jc of YBa2Cu3O7/insulator/YBa2Cu3O7 trilayers

We have studied critical current density (Jc) in YBa2Cu3O7−x/insulator/YBa2Cu3O7−x trilayers as the interlayer magnetic coupling is reduced by increasing the insulator thickness (tI). Although the thickness of both YBa2Cu3O7−x layers were fixed at 0.25μm, the self- and weak-field Jc of the trilayer sample increases monotonically with tI from the lowest value for a 0.5-μm-thick YBa2Cu3O7−x film at tI=0, and saturates at the Jc value for a 0.25-μm-thick YBa2Cu3O7−x film at tI≈20nm. This result suggests an intimate correlation between Jc and magnetic coupling of vortex segments in two YBCO layers.