Oxygen annealing: a tool for tailoring the pinning landscape in GdBCO thin films

Oxygen annealing is an important and well-known step in every REBa2Cu3O7 (REBCO, RE=rare earth) based superconducting thin film preparation, which is responsible for the formation of the superconducting phase. Within decades, various aspects of oxygen annealing such as anisotropy of the diffusion coefficient, diffusion in bulks and thin films as well as correlation between superconducting properties and annealing parameters have been thoroughly investigated. However, the correlation between oxygen annealing parameters and the defect morphology and, thus, resulting transport properties have not been established.

In this work, we focus on oxygen annealing of PLD-grown pristine GdBa2Cu3O7-ẟ (GdBCO) superconducting thin films. In order to study the effect of oxygen annealing, two approaches have been considered: in-situ (annealing in PLD chamber) and ex-situ (annealing in a tubular furnace). Annealing temperature and oxygen pressure were varied as main parameters, which affect the structural and transport properties, in addition, two ways of tailoring the GdBCO thin film microstructure are shown.