Strong flux pinning by columnar defects with directionally dependent morphologies in GdBCO-coated conductors irradiated with 80 MeV Xe ions

摘要

We show that Xe ion irradiation with 80 MeV to GdBa(2)Cu(3)Oy-coated conductors creates different morphologies of columnar defects (CDs) depending on the irradiation angles theta(i) relative to the c-axis: continuous CDs with a larger diameter are formed for oblique irradiation at theta(i) = 45 degrees, whereas the same ion beam at a different angle (theta(i) = 0 degrees) induces the formation of discontinuous CDs. The direction-dependent morphologies of CDs significantly affect the angular behavior of the critical current density J(c). In particular, low-energy irradiation defects induce further improvement of J(c) in a unique combination of irradiation angles of theta(i) = 0 degrees and +/- 45 degrees: discontinuous CDs at theta(i) = 0 degrees and crossed CDs at theta(i) = +/- 45 degrees provide correlated pinning in a wide angular range, which is more strongly enhanced by each other via the pinning of kinks. (C) 2020 The Japan Society of Applied Physics