Fig. 6: Comparison of XANES spectra with DFT calculated spectra from selected defect models.

a Schematic diagrams showing the Frenkel and O(1) vacancy defects. Comparison of the pristine, 1016 He+ irradiated and Ar annealed samples with the pristine, Frenkel and O(1) vacancy defect models for YBCO, for b \(\hat{E}\)∣∣c and c \(\hat{E}\)∣∣a/b with the \(\hat{E}\)∣∣a/b modelled spectra being the average of the a and b spectra. d, e Show the corresponding difference spectra with the experimental He+ irradiated and Ar annealed spectra shown relative to the experimental pristine spectra, and the Frenkel and O(1) vacancy models shown relative to the pristine model.