GdBaCuO and YBaCuO Long Coated Conductors by IBAD-PLD Method—Enhancement of Production Speed and Critical Current in a Magnetic Field

We have been developing long coated conductors with high critical current, $I_{\rm c}$, by multi-plume and multi-turn pulsed laser deposition (MPMT-PLD) method. In addition to ${\hbox{YBa}}_{2}{\hbox{Cu}}_{3}{\hbox{O}}_{7-{\rm X}}$ (YBCO) coated conductors, we have recently succeeded in fabricating long ${\hbox{GdBa}}_{2}{\hbox{Cu}}_{3}{\hbox{O}}_{7-{\rm X}}$ (GdBCO) coated conductors. The 30 m long and 60 m long GdBCO conductors showed higher $J_{\rm c}$ values in a magnetic field and lower anisotropy than the conventional long YBCO conductor. Critical current, $I_{\rm c}$, of the GdBCO at 3 T and 77 K was more than 20 A, which was three times larger than that of the YBCO long coated conductor. To demonstrate the high performance of GdBCO, we fabricated GdBCO coils and compared it with the YBCO coil. The GdBCO coil was successfully energized up to large $I_{\rm c}$'s of 74.2 A and 184.8 A at 77 K and 64 K, which generated magnetic field of 0.5 T and 1.2 T at 64 K and 77 K. We confirmed that the GdBCO conductor is more promising than the YBCO conductor for the application because its superior transport properties in a magnetic field.