Flux pinning properties of splayed columnar defects ranging from B || c-axis to B || ab-plane in GdBCO coated conductors

• GdBCO CCs were irradiated with 270 MeV Xe ions to install splayed CDs.
• CDs crossing relative to c-axis makes a single peak of Jc around B || c.
• CDs crossing relative to ab-plane cause a dip structure of Jc at B || ab.
• Splayed CDs do not seem to work as effective PCs for flux lines at B || ab.

GdBa2Cu3Oy (GdBCO) coated conductors were irradiated using 270 MeV Xe ions at crossing angles ±θi relative to the c-axis, in order to clarify the flux pinning properties of splayed columnar defects (splayed CDs) not only around B || c-axis, but also around B || ab-plane. For the splayed CDs with smaller θi (i.e. crossing around the c-axis), a single peak is observed around B || c-axis in the angular dependence of critical current density Jc, which are attributed to the splay effect by the crossed CDs. For the splayed CDs with larger θi (i.e. crossing around the ab-plane), on the other hand, two sharp Jc peaks emerge near two irradiation angles ±θi and the Jc at B || ab-plane indicates not a peak but a dip structure. With diminishing the crossing angles of CDs relative to ab-plane, the value of Jc at B || ab-plane build up with the dip structure remained. These results suggest that the splayed CDs contribute to the flux pinning around the ab-plane, but do not induce the splay effect at B || ab-plane.