Inverted-parabolic and weak strain dependencies on the critical current in practical 110 and 100 oriented REBCO tapes

Osamura, Kozo*; Machiya, Shutaro*; Kajiwara, Kentaro*; Kawasaki, Takuro   ; Harjo, S.   ; Zhang, Y.*; Fujita, Shinji*; Iijima, Yasuhiro*; Hampshire, D. P.*

In the commercial coated conductor tapes, the twinned structure of REBCO (REBaCuO, RE = Y and Gd) is characterized as either 100 or 110 orientation based on the tape length direction. In this study, we investigate the effects of the two different twinned structures on the critical current of the REBCO tapes by combining; transport critical current and synchrotron radiation diffraction measurements. For the tapes with 100 oriented twins, we observed the inverted parabolic strain behavior on the uniaxial strain dependence of . In contrast, the ones with 110 oriented twins showed a weak strain behavior without any maximum appeared in the strain dependence. Such a different uniaxial strain dependence was analyzed by using the one-dimensional twin model with different fractional lengths of A-domains and B-domains of REBCO twins. This model explains the essential features of the different uniaxial strain dependence we observed.