Variable Temperature Transport Critical Current Measurements on REBCO Coated Conductors

• Other Authors: Francis, Ashleigh Renee (author)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Materials science
• Online Access: http://purl.flvc.org/fsu/fd/2019_Spring_Francis_fsu_0071N_15241

REBCO coated conductors have recently become viable for high field superconducting magnets, but their use brings new challenges. Knowledge of the transport critical current density over a wide range of magnetic field and temperature, Jc(B, T), is essential to accurately model quench behavior and assure protection in REBCO superconducting magnets. At the National High Magnetic Field Laboratory (NHMFL), 12 km of REBCO tapes were purchased and characterized at 4.2 Kelvin (K) with field orientation B⊥tape and at 18° off-axis to select tapes for the construction of the all-superconducting 32 T user magnet that successfully reached field recently. Of the tapes selected for 32 T, three were chosen for additional Jc(B, T) characterization from 4.2 K to 75 K and fields from 1 T to 15 T in the B⊥tape orientation. A new probe was designed to accommodate these measurements on 4mm wide REBCO tapes up to 700 Amps. We found that the transport Jc(B, T) dependence described using Ginzburg-Landau models of vortex pinning for HTS fit well to a power law for Jc(B) and to an exponential temperature dependence for T < 45 K and 3 T < B < 15 T. A fourth tape from the 32 T magnet was then selected to test the predictability of our modeling. Using this extensive data set, the correlation between Jc(B, 4.2 K) and Jc(B , T) enabled us to predict Jc(B, T) for all tapes procured for the 32 T magnet with an accuracy of 10% or less for T < 40 K. === A Thesis submitted to the Department of Mechanical Engineering in partial fulfillment of the requirements for the degree of Master of Science. === Spring Semester 2019. === April 19, 2019. === Flux Pinning, High Temperature Superconductivity, Magnet Design, REBCO, Superconductivity, Transport Critical Current Measurements === Includes bibliographical references. === David C. Larbalestier, Professor Directing Thesis; Fumitake Kametani, Committee Member; Wei Guo, Committee Member; Dmytro Abraimov, Committee Member.