Enhanced flux pinning in YBa₂Cu₃O_7−δthin films using Nb-based double perovskite additions

Abstract

The addition of a new niobate double perovskite pinning phase to YBa2Cu3O7−δ thin films grown by pulsed laser deposition is reported. The YBa2NbO6 phase self-assembles into stacks of ∼10 nm second phase particles, aligned with the c-axis of the YBa2Cu3O7−δ. The YBa2Cu3O7−δ/YBa2NbO6 composite thin films have enhanced critical current, by a factor of 2, at 1 T () over the pure YBa2Cu3O7−δ, whilst maintaining a high transition temperature. Niobium does not substitute in the YBa2Cu3O7−δ matrix. This, together with the high stability of the second phase formed, makes it an ideal pinning additive.