[WBP1] Conductor Processing & Evaluation

[WBP1-20] The in-field J_c properties of TFA-MOD (Y_0.77Gd_0.23)Ba₂Cu₃O_y CCs with a high volume of BaHfO₃ NPs

*Yuki OGIMOTO¹, Keisuke Aoto¹, Masashi Miura^1,2 (1. Seikei Univ. (Japan), 2. JST-FOREST (Japan))

Keywords:

REBCO,YGdBCO,TFA-MOD,Jc,BHO,pinning center,nanoparticle

The REBa₂Cu₃O_y (RE: rare earth element) superconductors with high critical temperature (T_c) and critical current density (J_c) are expected to be used for practical superconducting applications. However, the in-field J_c property rapidly decreases in increasing applied magnetic field by the movement of vortices penetrating a superconductor. To solve this problem, we have introduced vortex pinning centers of BaHfO₃ (BHO) nanoparticles (NPs) up to 12 vol.% into Trifluoroacetate Metal Organic Deposition (TFA-MOD) method-grown (Y_0.77Gd_0.23)Ba₂Cu₃O_y ((Y,Gd)BCO) coated conductors (CCs) [1,2]. The highest in-field J_c property was obtained for CCs with 12 vol.% of BHO NPs owing to their high nanoparticle density (N_p, and J_c ∝ N_p) [1,2]. Toward higher in-field J_c properties it is very important to clarify the effect of higher doping volumes of BHO NPs.In this work, to investigate the influence of volumes of BHO NPs over 12 vol.%, we fabricated (Y,Gd)BCO CCs with different BHO NPs contents up to 16 vol.% using the TFA-MOD method. For CCs with 16 vol.% of BHO NPs, the degradation of T_c, self-field and in-field J_c properties were observed compared to the CCs with 12 vol.% of BHO NPs. Based on these results and transmission electron microscopy (TEM) analysis, not only the size of the BHO NPs, but also the superconducting matrix itself might be affected by a high volume of BHO NPs. Detailed in-field J_c properties and microstructures for (Y,Gd)BCO with 16 vol.% of BHO NPs will be presented. Acknowledgements: This work was supported by JST-FOREST (Grant Number JPMJFR202G). A part of this work at Seikei University was supported by JSPS KAKENHI (23H01453 and 23KK0073). References:[1] M. Miura et. al., NPG Asia Materials 9 (2017) e447.[2] M. Miura et. al., NPG Asia Materials 14 (2022) 85.