成長環境がTFA-MOD (Y,Gd) BCO 線材の超伝導特性に及ぼす影響

Abstract

Trifluoroacetates-Metal Organic Deposition (TFA-MOD) (Y,Sm)Ba_2Cu_3O_y (YSmBCO) coated conductors (CCs) have showed higher critical current densities (J_c) compared with YBa_2Cu_3O_y (YBCO) CCs. However, the optimum conditions of the maximum heating temperatures (T) and the oxygen partial pressures (PO_2) to get high self-field J_c (J_c^<s.f.>) values (more than 3.0[MA/cm^2]) of the YSmBCO CCs is narrow. Therefore, the YSmBCO CCs is unsuitableness to produce a long coated conductor. In this study, we fabricated the TFA-MOD YGdBa_2Cu_3O_y (YGdBCO) CCs with different T and PO_2 to investigate the influence of these fabrication conditions on superconducting properties of CCs. We confirmed that the optimum conditions of T-PO_2 to get the high J_c^<s.f.> values of the YGdBCO CCs are wider than that of the YSmBCO CCs. From XRD patterns, the fraction of a-axis oriented grains at the low T region for the YGdBCO CCs is lower than that for the YSmBCO CCs.