Critical current density above 15MAcm-2 at 30K, 3T in 2.2μm thick heavily-doped (Gd,Y) Ba2Cu3Ox superconductor tapes

A critical current (I-c) value of 3963 A/12 mm, corresponding to a critical current density (J(c)) of 15 MA cm(-2) has been achieved at 30 K, 3 T in the orientation of field parallel to the c-axis (B parallel to c) in 2.2 mu m thick film (Gd,Y) BaCuO tapes with 20 mol% Zr addition made by metal organic chemical vapor deposition. This Jc level is more than a factor of four higher than the Jc values of 7.5 mol% Zr-added tapes, which are an industry benchmark. The critical current values in a magnetic field of 3 T parallel to the c-axis in the 2.2 mu m thick, 20 mol% Zr-added tape reached 2833 A/12 mm (10.1MA cm(-2)), 1881 A/12 mm (7.1MA cm(-2)) and 805 A/12 mm (3.1 MA cm(-2)) at 40 K, 50 K and 65 K respectively. Such high critical current values were possible because of maintaining a strong alignment of BaZrO3 nanocolumns along the c-axis over the entire film thickness.