2014 年 49 巻 3 号 p. 163-168
The introduction of artificial pinning centers such as BaZrO3 (BZO), BaSnO3 (BSO) and BaHfO3 (BHO) nano-rods into REBCO film is effective to improve in-field critical currents (Ic). In particular, BHO doping into Gd1Ba2Cu3O7-δ (GdBCO) has been found to exhibit high in-field Ic values under a wide range of temperatures and magnetic fields. However, the increase of Ic values of the GdBCO + BHO system exhibited somewhat of a saturated manner, with thickening of the superconducting films to more than 3μm. In this work, a new combination of Eu1Ba2Cu3O7-δ (EuBCO) + BHO system was investigated using the IBAD/PLD process to improve in-field performance in thick films. As a result, it was found that a EuBCO + BHO thick film showed an extremely high Ic, min property of 141 A/cm-w at 77 K and 3 T. A 93.7-m-long EuBCO + BHO CC estimated Ic value of 108 A/cm-w at 77 K and 3 T was successfully fabricated.