Over 15 MA/cm(2) of critical current density in 4.8 µm thick, Zr-doped (Gd,Y)Ba(2)Cu(3)O(x) superconductor at 30 K, 3T

An Advanced MOCVD (A-MOCVD) reactor was used to deposit 4.8 µm thick (Gd,Y)BaCuO tapes with 15 mol% Zr addition in a single pass. A record-high critical current density (J(c)) of 15.11 MA/cm(2) has been measured over a bridge at 30 K, 3T, corresponding to an equivalent (I(c)) value of 8705 A/12 mm width. This corresponds to a lift factor in critical current of ~11 which is the highest ever reported to the best of author’s knowledge. The measured critical current densities at 3T (B||c) and 30, 40 and 50 K, respectively, are 15.11, 9.70 and 6.26 MA/cm(2), corresponding to equivalent Ic values of 8705, 5586 and 3606 A/12 mm and engineering current densities (J(e)) of 7068, 4535 and 2928 A/mm(2). The engineering current density (J(e)) at 40 K, 3T is 7 times higher than that of the commercial HTS tapes available with 7.5 mol% Zr addition. Such record-high performance in thick films (>1 µm) is a clear demonstration that growing thick REBCO films with high critical current density (J(c)) is possible, contrary to the usual findings of strong J(c) degradation with film thickness. This achievement was possible due to a combination of strong temperature control and uniform laminar flow achieved in the A-MOCVD system, coupled with optimization of BaZrO(3) nanorod growth parameters.