High-temperature superconducting CORC^® wires with record-breaking axial tensile strain tolerance present a breakthrough for high-field magnets

Cuprate high-temperature superconductors (HTS), such as RE-Ba2Cu3O7-δ(REBCO, RE=rare earth), (Bi,Pb)2Sr2Ca2Cu3O10-x(Bi-2223) and Bi2Sr2CaCu2O8-x(Bi-2212), have enabled the development of high-field superconducting magnets capable generating magnetic fields far exceeding 20 T. The brittle nature HTS requires elaborate means to protect them against high stresses strains associated with magnet operation, so has prevented reliable from becoming a reality. Here we report more than tenfold increase in irreversible strain limit under axial tension (eirr) over 7 % composite conductors, high-current Conductor on Round Core (CORC®) containing REBCO tapes wound helical fashion around round metal core. Minimizing tape winding pitch mechanically decouples film overall conductor. behave springs, limiting rate at which applied is transferred ceramic film. In addition, high-strength alloy cores allow critical stress (σcrit) initial degradation CORC® conductors occurs exceed 600 MPa, making one strongest available. Mechanically decoupling films conductor allows effective protection operating magnets. This breakthrough presents monumental shift for technology, bringing compact fusion machines, next generation particle accelerators, 40 – 60 T research solenoids within reach. Introduction