REBa2Cu3Oy (REBCO) grown by reel-to-reel pulsed laser deposition (RTR-PLD) coated conductors (CCs) are expected to be used in magnet application because of their excellent high-field superconducting properties. However, further improvement of the critical current density (Jc) is still required for practical use. The introduction of BaHfO3 nanoparticles (BHO NPs) [1,2] and irradiation-induced defects  as flux pinning centers have been reported to improve in-field Jc properties. Recently, S. Eley et al. reported the enhancement of Jc for REBCO CCs with oxygen-irradiated defects .
In this work, to investigate the effect of coexisting BHO NPs and irradiation-induced defects on the superconducting properties of RTR-PLD (Eu,Er)Ba2Cu3Oy CCs, we prepared (Eu,Er)BCO+BHO CCs with various irradiation fluences. Although Tc and Jc decreased immediately after irradiation, they recovered almost all of their original properties after oxygen annealing treatment. The (Eu,Er)BCO+BHO CCs with 1×1013 O ion/cm2 show higher in-field Jc properties compared to that in unirradiated (Eu,Er)BCO+BHO CCs at high temperature (65 - 77 K). To understand these Jc improvements for oxygen-ion irradiated (Eu,Er)BCO+BHO CCs, we used a simple pinning model in the analysis . We see that the calculated Jc using our pinning model is good agreement with the experimental Jc. The pinning model and detailed in-field superconducting properties for (Eu,Er)BCO+BHO CCs with oxygen irradiated defects will be presented.
This work at Seikei University is supported by JST-FOREST (Grant Number JPMJFR202G). A part of this work at AIST was supported by the New Energy and Industrial Technology Development Organization (NEDO).
 M. Miura et al., NPG Asia Materials 9 (2017) e447.
 M. Miura et. al., NPG Asia Materials (accepted on Sep. 6th, 2022)
 M. Leroux et al., Appl. Phys. Lett. 107 (2015) 19260.
 S. Eley et al., Supercond. Sci. Technol. 30 (2017) 015010.
Keywords: REBCO, ion iradiation, critical current, PLD