Cu-Ni-Mn合金を複合化した超極細多芯交流用Nb-Ti超電導線材

交流損失

抄録

AC loss characteristics of sub-micron filament Nb-Ti superconducting wires with Cu-Ni-Mn alloy matrix for AC use are described. To investigate the relationship between the proximity effect and hysteresis loss, the Nb-Ti superconducting wires are prepared, 1) changing Ni (10 and 30wt%) and Mn (0-1.78wt%) contents in Cu-Ni-Mn alloy matrix, 2) the variation of ratio of filament spacing (d_n) to filament diameter (d_f). The addition of Mn to Cu-Ni matrix reduces the proximity effect by magnetic scattering and the allowed efficient Mn content to reduce hysteresis losses of Nb-Ti filaments is in the range of 0.9wt% to 1.78wt%. The relationships between d_n and hysteresis losses were investigated and the optimum d_n to reduce the proximity effect were d_n=0.2μm (Cu-10%Ni matrix), d_n=0.08μm (Cu-10%Ni-0.9%Mn), d_n=0.052μm (Cu-30%Ni-0.9%Mn) and d_n=0.048μm (Cu-30%Ni-1.34%Mn). Weak coupling due to the proximity effect has no influence on increasing hysteresis loss at an amplitude field of more than B_m=0.6-0.8T.