Characteristic Strain Response of ${\rm I}_{\rm c}$ in SmBCO Coated Conductor Tapes Under Magnetic Field at 77 K

SmBCO and YBCO coated conductors (CC) showed different critical current, I_c degradation behavior with strain showing different I_c peak position under self field. Strain effect on I_c under magnetic field in REBCO CC tapes was investigated in order to measure and to describe its tolerance and degradation behavior. Katagiri-type tensile testing apparatus was adopted in which magnetic field was applied parallel to the c-axis of coating film using 10 T superconducting magnet at 77 K. Both strain gauge and Nyilas double extensometers were used to measure the strain. In all the REBCO CC tapes investigated, I_c(ε, B) strongly depends on magnetic field and their degradation behavior depends on the kind of HTS film and fabrication technique adopted. Differently with YBCO CC tapes, SmBCO CC tapes showed increasing I_c strain sensitivity with increasing magnetic field at 77 K and the irreversible strain limit was magnetic field independent over the entire field range studied.