In-field performances of commercial REBCO tapes below liquid nitrogen temperatures

• Jc(H, θ) for four commercial REBCO tapes were measured between 30 and 77 K.
• The in-field Jc characteristics of Zr-doped REBCO tape vary among spools.
• Different REBCO tapes show very different in-field performances.
• The relative superiority of REBCO tapes varies with temperature.

We investigated critical current density (Jc) characteristics of commercial REBCO tapes of four manufacturers at temperatures between 30 and 77 K in magnetic fields up to 5 T. We first examined variation in the Jc characteristics of two Zr-doped REBCO tapes (SuperPower) of the same specifications, which are found to be quite different, indicating that the in-field Jc characteristics due to artificial pinning centers vary among spools or along the length of tape.We then investigated in-field performances of four different commercial REBCO tapes (AMSC, Fujikura, SuNAM, SuperPower), calculating performances of coils using their magnetic-field angle dependences of Jc. The REBCO tapes are found to give very different in-field performances depending on the strength and direction of field they experience, and their relative superiority is observed to vary with temperature.