Paper detail

Radiation Damage and Thermal Recovery of Perovskite Superconductor Yttrium Barium Copper Oxide

High temperature superconducting materials are being considered to generate the magnetic fields required for the confinement of plasma in fusion reactors. The present study aims to assess the microstructural degradation resulting from ion implantation at room temperature under two implantation conditions in Yttrium Barium Copper Oxide (YBCO) tapes. Xray Diffraction (XRD) and high resolution characterisation techniques including Atom Probe Tomography (APT) and Transmission Electron Microscopy (TEM) analyses were used to correlate alterations in superconducting behaviour measured using a Magnetic Properties Measurement System (MPMS) to amorphization and recovery caused by ion implantation. TEM analysis was performed to depth profile the degree of crystallinity (or lack thereof) on irradiated samples. SRIM predicted the damage depth at 900 nm below the sample surface of the 2 MeV Xe implanted sample and 450 nm beneath the surface of the 0.6 MeV Xe implanted sample. 2 MeV Xe implantation caused the superconducting temperature to decrease by 10 K and the critical current density to display a 10 fold reduction. Post irradiation heat treatments up to 600C caused recrystallisation of the irradiated layer, but also oxygen loss and alterations in grain size. The recrystallised grain orientation was random in TEM lamellae, however, bulk samples re-grew along the original crystal orientation provided that some of the original material was not amorphized (ie if they nucleated on crystalline YBCO). This is extremely promising for the thermal recovery of tokamak components.