Optimization of interim heat-treatment condition on TFA-MOD process for fabrication of Y0.77Gd0.23Ba2Cu3Oy coated conductors with BaHfO3

We have optimized the interim heat-treatment (IHT) time in trifluoroacetate based metal organic deposition process on fabrication of the BaHfO3 (BHO) doped Y0.77Gd0.23Ba2Cu3Oy (YGdBCO) coated conductor (CC) in order to further improve the in-field critical current density (J(c)) performance. The in-field J(c) values of 0.6 mu m-thick BHO doped YGdBCO CCs increased with increasing the IHT time within 90 min. The highest critical current density (J(c)) value of 0.86 MA/cm(2) at 77 K in 3 T (B//c) was obtained for 0.6 mu m-thick BHO doped YGdBCO CC with IHT time of 90 min. CCs with IHT time shorter than 90 min had relative low in-field Jc performance but high self-field J(c) performance. It can be caused by the insufficient transformation to BaF2 in IHT which is a reason for the relatively large BHO particles. In the case of applying IHT for longer time than 90 min, coarsening of CuO particles in precursor films was suggested and degradation of self- and in-field J(c) performances were observed.