Characteristics of REBCO Coated Conductors for 25 T Cryogen-Free Superconducting Magnet

A 25 T cryogen-free superconducting magnet is under development at the High Field Laboratory for Superconducting Materials (HFLSM), Institute for Materials Research (IMR), Tohoku University. Fujikura has manufactured and supplied REBCO coated conductors for the 25 T cryogen-free superconducting magnet. In-field critical current (I
_c
) properties in high magnetic fields at lower temperatures below 20 K and mechanical properties are important for design of these superconducting magnets. However, there is insufficient data of I
_c
properties in high magnetic fields above 15 T. In this work, in-field I
_c
properties at 20 K, 15 T of several samples cut from commercial coated conductors are evaluated at HFLSM, IMR, Tohoku University. The correlations between I
_c
at 20 K, 15 T and I
_c
at 77.3 K are compared. As a result, it is confirmed that I
_c
at 20 K, 15 T have a stronger correlation with in-field I
_c
at 77.3 K rather than I
_c
at 77.3 K, self-field. In addition, tensile strengths at 77.3 K of more than 30 samples of coated conductors are also evaluated.