Optimization of Transport Critical Currents at 4.2 K – 20 K at Magnetic Fields Up to 31 T for MOCVD REBCO Conductors With Variable Zr and Growth Conditions

The critical current,$I_{\mathrm{c}}$, of REBCO full-width 4 mm short samples made by metal-organic chemical vapor deposition (MOCVD), optimized for high-field applications, were measured at magnetic fields perpendicular to sample plane up to 31.2 T in resistive magnets and temperature range${\text{4.2}}\,{\text{K}}$–55 K. Dependencies of$I_{\mathrm{c}}$, critical current density ($J_{\mathrm{c}}$), and pinning force density ($F_{\mathrm{p}}$) on Zr doping and REBCO growth conditions were studied. SEM images of cross-section and top view of the REBCO layers for tapes with 15%, 20%, and 25% Zr doping show dense REBCO layers without secondary phases or porosity. REBCO tapes with 20% and 25% Zr doping perform better in transport$I_{\mathrm{c}}$(T,$\mu _{o}H$) tests at 20 K and 20 T conditions than tapes with lower Zr doping and can be promising candidates for applications focusing on magnetic plasma confinement.