High field magnets for nuclear confinement fusion reactors are a prime application for high temperature superconductors, with a multitude of projects currently in various stages of development. However, compact fusion reactors expose the superconducting magnet system to a destructive fast neutron flux, which degrades the superconducting properties and thus limiting reactor lifetime.

GdBCO-based thin films were irradiated with neutrons in a TRIGA Mark-II research reactor. To protect the films against deterioration and loss of thickness in the harsh conditions during irradiation the films are covered with a nonconductive protective layer, except at the current and voltage contacts. Resistivity and Hall effect measurements at magnetic fields up to 15 T were performed prior and post irradiation, with the goal of extracting the evolution of the normal state resistivity, mobility and possible changes in charge carrier density. Changes of the Hall angle yield information about the change in scattering rate.

To investigate the temperature stability of defects introduced via neutron irradiation short pieces of commercial coated conductors, with the copper layer removed completely and the silver layer only between the voltage contacts, were prepared. Those samples were annealed in pure oxygen while slowly ramping the temperature and measuring the resistivity of the superconducting layer in-situ. The in-situ measurement was performed before the irradiation until the temperature dependent resistivity became fully reversible, to remove any defects introduced during manufacturing that are not stable during the heat treatment. Thus, comparison between the increasing and decreasing branch of the resistivity curve of the irradiated sample yields information about the temperature stability of defects introduced via neutron irradiation.