High Jc YBCO current lead by unidirectional solidification

The unidirectional solidification method was used in order to synthesize current leads of high Jc by different traveling rates for different initial compositions of YBa2Cu3O6+δ (Y123) + x% Y2BaCuO5 (Y211) (x= 10, 20, 30, 40 and 50) with the addition of 0.5 wt.% Pt. The highest Jc was found in the sample with 30% excess Y211 in the initial composition by the higher traveling rate, namely 3 mm h−1, adjusted to prevent the formation of polycrystals. In this 1.56 mn × 60 mm sample the values of transport Ic and Jc were 1370 A and 71700 A cm−2, respectively, which were obtained by the conventional DC four-probe method with criterion of 1 μV cm−1 at 77 K and self-field.