Synergetic evolution of the microscopic crystal orientation and macroscopic superconducting properties of REBCO tape under sever deformation

This study investigates crystal orientation evolution at microscopic level, and changes in the superconducting properties at macroscopic level of rare-earth-barium-copper-oxide (REBCO) superconductor tape under severe deformation. At the microscopic level, in-situ electron backscatter diffraction is used for real-time observation of the crystal orientation evolution during the entire tensile process. At the macroscopic level, the critical current ( I_c) value and I_c angle dependence performance are systematically measured under different applied tensile stresses. By comparing the microscopic and macroscopic results, the synergetic evolution mechanism between them is successfully established. Stress at the initial descent point of the I_c value excellently fits the one where the (001)[100] orientation sharply decreases, thereby revealing the real I_c degradation mechanism of REBCO tapes. The application of a moderate applied tensile stress can increase the in-field I_c value and pinning force because new generated defects and strains act as pinning centers. A higher tensile stress can destroy the biaxial texture of the REBCO layer and become a significant barrier to the supercurrent flow. This research elucidates the REBCO degradation mechanism and may assist manufacturers in improving the electromechanical properties of commercial REBCO tape.