Investigation of thick PLD-GdBCO and ZrO₂doped GdBCO coated conductors with high critical current on PLD-CeO₂capped IBAD-GZO substrate tapes

Abstract

In order to increase the critical current, I c , we have fabricated thick GdBa 2 Cu 3 O 7−δ (GdBCO) coated conductors (CCs) by the pulsed laser deposition (PLD) method on PLD-CeO 2 /ion-beam assisted deposition (IBAD)-Gd 2 Zr 2 O 7 (GZO)/hastelloy metal substrate tapes. The highest critical current value was 522 A cm −1 for a thickness of 3.6 µm in self-field at 77 K. It was found that a low volume fraction of a-axis orientated grains was obtained in the thick GdBCO CCs, compared to YBa 2 Cu 3 O 7−δ (YBCO) CCs. Consequently, the GdBCO CCs showed higher critical current density (J c ) than YBCO CCs in all thicknesses from 0.2 to 3.6 µm. Furthermore, we have succeeded in improving I c in a magnetic field by the introduction of artificial pinning centres using a 5 mol% ZrO 2 doped GdBCO target. In the measurement of the I c dependence on the magnetic field angle, θ , I c was much improved, especially at 0 • , i.e., with the magnetic field parallel to the c-axis. The I c value at 3 T was 59.5 A cm −1 at 0 • and it showed a minimum of 42.3 A cm −1 at 82 • for 2.28 µm thick CC. The minimum value in the angular dependence of I c at 3 T was about five times higher than that of YBCO CC and two times higher than that of pure GdBCO CC.

Growth of simplified buffer template on flexible metallic substrates for YBa2Cu3O coated conductors

“…To induce biaxial texture in buffer layers, two well established techniques have been explored to induce crystallographic alignment, i.e., incident substrate deposition [7,8] and ion-beam-assisted deposition (IBAD) [9e11]. In the IBAD approach, yttria-stabilized zirconia and Gd 2 Zr 2 O 7 are the mostly explored texturing materials [12,13]. Nevertheless, the slow evolution procedure of biaxial texture (with thickness >500 nm) for these fluorite-structured materials limits their application prospect.…”

Enhanced flux pinning by BaZrO3 and (Gd,Y)2O3 nanostructures in metal organic chemical vapor deposited GdYBCO high temperature superconductor tapes

“…5 In particular, columnar structures of 5-100 nm in diameter comprised of BZO nanodots, aligned along the c-axis of REBCO, can be formed in the PLD REBCO films. [6][7][8][9] These c-aligned columnar defects were found to be very effective in pinning, especially when the magnetic field B is applied parallel to the c-axis of REBCO. However, the aligned nanometer sized columnar defects were not previously observed in REBCO films grown by metal organic chemical vapor deposition ͑MOCVD͒, and the Zr doping was not substantially proven to enhance performance of MOCVD grown REBCO films until we recently demonstrated that the I c at 77 K and 1 T for MOCVD grown Zr:GdYBCO tapes could be of a factor of two higher than those for GdYBCO tapes without Zr-additions.…”

Jc–B characteristics of (RE,RE′)–Ba–Cu–O films on PLD-CeO2/IBAD-GZO/metal substrates

“…4, the J c and the T c of the GdRE-123 films and Nd-123 film under magnetic field are plotted with our previous data of RE-123 [2,3,9,11]. The horizontal axis indicates ionic radius of the RE for the RE-123 or average ionic radius of the Gd and RE for the GdRE-123.…”