H. Kutami

High-speed deposition of high-quality RE123 films by a PLD system with hot-wall heating

We have studied the use of a hot-wall heating system for producing GdBa2Cu3O7?X (Gd123) films with large critical current (Ic), stably, at high speed, by a pulsed laser deposition (PLD) method. We achieved a material yield from the PLD system with hot-wall heating of about 50% through optimization of the evaporation conditions. With the PLD system, we were able to fabricate a Gd123 film about 20?cm long with a high Ic of 997?A (77?K, self-field) at about 6??m thickness. The maximum Ic that we achieved for a Gd123 film about 2?cm long was 1040?A (77?K, self-field) at about 6? ?m thickness. Furthermore, we were able to form a Gd123 film about 1? ?m thick and 20?cm long with an Ic of 352?A (77?K, self-field) at a high speed of 60? m?h?1 using high laser power. For the production of long conductors coated with RE123 (REBa2Cu3O7?X, where RE stands for rare earth) using hot-wall heating, it was found that RE123 coated conductors over 100?m long with Ic of over 200?A had uniform Ic distributions with ? 2% variations in the direction of the length.

Remarkable progress in fabricating RE123 coated conductors by IBAD/PLD technique at Fujikura

Increase of production rate and improvement of quality for RE123 coated conductors have been tried. In-plane texturing of MgO was attempted by the IBAD system with the world largest ion source. As a result of optimizing condition in large deposition area, the dramatically high throughput of 1000 m / h was realized to obtain the IBAD-MgO with Δ 600 A except some locations was obtained at the throughput of 15 m / h. In addition to the speed-up, the very high Ic of 1040 A was also achieved by the hot-wall heating PLD system.

Progress in Scale-Up of RE-123 Coated Conductors With

By an IBAD/PLD method, a 500 m-length high-performance GdBa₂Cu₃O_x (GdBCO) coated conductor with BaZrO₃ (BZO) was fabricated. End-to-end I_c of the 503.5 m tape was 349.6 A/cm at 77 K, corresponding I_c times L value of 176,023 Am. New approaches to decrease the thickness of IBAD buffer layers were developed by combination of IBAD-MgO(111) and IBAD-Gd₂Zr₂O₇ (GZO). The maximum Jc of the GdBCO on the buffer layer was 550 A/cm. We also started to investigate IBAD-MgO(OOl) by using a large IBAD system with a 110 cm times 15 cm ion source. A 50 m-length IBAD-MgO tape with DeltaPhi of 13deg was fabricated at a 100 m/h-1 pass. Insulated REBCO wires with Cu or Ni-Cr lamination were developed using 5 mm-wide conductors sliced from 10 mm-wide IBAD/PLD tapes. Practical long insulated wires were supplied for several prototypes of motors, transformers and fault current limiters in fiscal 2007.