Difference of AC Losses Between Nonstriated and Striated Tape and Applicability of Temperature Scaling Law to Stacked Striated Tape

The ac loss properties of stacks of nonstriated and striated REBa₂Cu₃O_y (REBCO, RE = rare earth elements, Y, Gd, Eu) superconducting tapes were investigated over a wide range of temperature and magnetic field amplitude, and compared with each other. The results obtained show that the penetration field (B_p), in which the magnetic flux front penetrates the center of the tape, increases with increasing number of stacked tapes (N) for the nonstriated tapes. In addition, the ac losses in the nonstriated tapes for a smaller magnetic field amplitude (B) than B_p decreases as N increases. On the contrary, for the striated tapes, B_p marginally depends on N and the ac losses also show slight variations with N. These phenomena seem to be due to the demagnetizing effect. It was shown that the ac losses in the striated REBCO and nonstriated tapes are scaled with temperature regardless of the number of stacked tapes. This suggests that the ac losses of REBCO tapes can be easily estimated for temperature measured in this study regardless of striating and stacking, provided that the impact level of temperature on the critical current at self-field and the ac losses at certain temperatures are known.