Broad Temperature Pinning Study of 15 mol.% Zr-Added (Gd, Y)–Ba–Cu–O MOCVD Coated Conductors

BaZrO₃ (BZO) nanocolumns have long been shown to be very effective for raising the pinning force Fp of REBa₂Cu₃O_x (REBCO, where RE = rare earth) films at high temperatures and recently at low temperatures too. We have successfully incorporated a high density of BZO nanorods into metal organic chemical vapor deposited (MOCVD) REBCO coated conductors via Zr addition. We found that, compared to the 7.5% Zr-added coated conductor, dense BZO nanorod arrays in the 15% Zr-added conductor are effective over the whole temperature range from 77 K down to 4.2 K. We attribute the substantially enhanced J_c at 30 K to the weak uncorrelated pinning as well as the strong correlated pinning. Meanwhile, by tripling the REBCO layer thickness to ~2.8 μm, the engineering critical current density J_c at 30 K exceeds J_c of optimized Nb-Ti wires at 4.2 K.