Development of multi-filamentated long EuBCO coated conductors with BHO doping by plane-plume PLD method

Long REBa₂Cu₃O_x (REBCO, RE: rare earth element) coated conductors with BaMO₃ (BMO, M: metal) doping have been expected for the industrial and commercial applications. It is known that critical current (I _c) of REBCO coated conductors (with or without artificial pinning centers doping) in magnetic field at high temperature is superior to the other superconducting wires. Especially, we have found that EuBa₂Cu₃O_x (EuBCO) coated conductors with BaHfO₃ (BHO) doping show higher critical current density (J _c) and I _c at high temperature in self and magnetic fields than those of YBa₂Cu₃O_x and GdBa₂Cu₃O_x coated conductors with BHO doping. However, in order to realize EuBCO coated conductors with BHO doping for various applications such as an armature coil, the much higher uniformity of not only longitudinal and but transversal I _c distributions of long REBCO coated conductors with high in-field performance for filamentary structure is required. The plane-plume PLD (pulsed laser deposition) method is performed by shortening the target-substrate distance and increasing the number of plumes with scan of X-Y axes directions to increase the deposition rate and averaging the deposition conditions which should relate to obtain the uniformity I _c distributions. We fabricated the EuBCO coated conductors with BHO doping (of 0.6 m length and 10 mm in width) by the combination of the ion-beam assisted deposition (IBAD) and the plane-plume PLD method and then we processed the multi-filamentary structure EuBCO coated conductors with BHO doping (of 8 filaments of 440 μm, 0.6 m in length and 5 mm in width) by using the excimer laser scribing to reduce the AC loss and to control the shielding current. I _c distributions in a width direction of this EuBCO coated conductor with BHO doping was improved as an uniformity of filament-I _c of 4.3 %.

Recently, we fabricated the 16 filamentary and 3 m long EuBCO coated conductor with BHO doping by IBAD / plane-plume PLD method. We confirmed that the hysteresis loss was reduce to 1/16 by a 16 filamentary EuBCO coated conductor with BHO doping comparing with EuBCO coated conductor with BHO doping without filamentation. (paper)