Full text loading...
Illustration of method for applying large axial strains to the superconducting sample, which is soldered on top of a Cu Be bending beam. Axial tension is applied by bending the beam in the direction shown in (a), whereas axial compression is applied by bending the beam in the opposite direction (b).
Dependence of the superconducting current density on applied axial strain in a copper laminated MOD-RABiTS sample at . The measurement was first taken at axial compressive strains (left side of plot), and is plotted as a function of strain, as shown by solid symbols. The applied compressive strain was released from (as indicated by the left arrow) and was remeasured at zero applied strain (open symbol near ). The applied strain did not return to zero, because of yielding in the sample substrate. The bending beam was then turned over in the four-point bender, while still submerged under liquid nitrogen, and was measured as a function of tensile strain (again shown by solid symbols on the right side of the plot). The superconducting current density starts degrading irreversibly at an applied tensile strain indicated by . The irreversible loss of critical current becomes evident when strain is partly released and is measured again (open symbols on the right side the plot).
Normalized superconducting current density is plotted as function of intrinsic strain over the range where changes reversibly for MOCVD-IBAD samples in (a) and for (hybrid) MOD-RABiTS samples in (b). No irreversible degradation in is measured under axial compression in the experiment. The solid data points represent samples with added copper stabilizer, which is indicated in the legend of both graphs by “ .” The solid lines describe the power-law function: . Values of the strain-sensitivity parameter are included in the figure.
Article metrics loading...