Higher critical currents yet faster vortex creep in EuBa2Cu3Oy films containing coherent artificial pinning centers

The electromagnetic properties of type-II superconductors depend on vortices—magnetic flux lines whose motion introduces dissipation that can be mitigated by pinning from material defects. The material disorder landscape is tuned by the choice of materials growth technique and incorporation of impurities that serve as vortex pinning centers. For example, metal organic deposition (MOD) and pulsed laser deposition (PLD) produce high-quality superconducting films with uncorrelated versus correlated disorder, respectively. Here, we study vortex dynamics in PLD-grown EuBa2Cu3Oy films containing varying concentrations of BaHfO3 inclusions and compare our results with those of MOD-grown (Y,Gd)Ba2Cu3Oy films. Despite both systems exhibiting behavior consistent with strong pinning theory, which predicts the critical current density Jc based on vortex trapping by randomly distributed spherical inclusions, we find striking differences in the vortex dynamics owing to the correlated versus uncorrelated disorder. Specifically, we find that the EuBa2Cu3Oy films grown without inclusions exhibit surprisingly slow vortex creep, comparable to the slowest creep rates achieved in (Y,Gd)Ba2Cu3Oy films containing high concentrations of BaHfO3. Whereas adding inclusions to (Y,Gd)Ba2Cu3Oy is effective in slowing creep, BaHfO3 increases creep in EuBa2Cu3Oy even while concomitantly improving Jc. Lastly, we find evidence of variable range hopping and that Jc is maximized at the BaHfO3 concentration that hosts creep of large vortex bundles or a Bose glass state. This study investigates vortex dynamics in pulsed laser deposition-grown EuBa2Cu3Oy films containing varying concentrations of BaHfO3 inclusions, with the results compared to metal organic deposition-grown (Y,Gd)Ba2Cu3Oy films.