Angular behavior of flux dynamics in YBCO films with crossed columnar defects around the ab-plane

We systematically investigated the influence of columnar defects (CDs) on the flux dynamics around B parallel to ab in YBa2Cu3O7-delta (YBCO) films, where two types of the crossed CD configurations with the crossing angle relative to the c-axis, theta(i) = +/- 30 degrees and +/- 60 degrees, were prepared by using 200 MeV Xe ion irradiation. The crossed CDs with theta(i) = +/- 30 degrees induce a peak of critical current density J(c) centered at B parallel to c, which suggests a typical entanglement state of flux lines. The J(c) at B parallel to ab, by contrast, is insensitive to the crossed CDs with theta(i) = +/- 60 degrees, which are crossing at +/- 30 degrees around the ab-plane. In addition, the behaviors of the glass-liquid transition temperature T-g and the dynamic critical exponent z indicate that the VG state develops at B parallel to ab not only for theta(i) = +/- 30 degrees but also for theta(i) = +/- 60 degrees. The difference in the contribution of CDs to the flux dynamics for between theta(i) = +/- 30 degrees and +/- 60 degrees also stands out at B parallel to CDs, where the magnetic field for theta(i) = +/- 60 degrees is more tilted toward the ab-plane: the J(c) peak at B parallel to CDs occurs in any magnetic field for theta(i) = +/- 60 degrees, whereas the correlated pinning state disappears in high magnetic fields for theta(i) = +/- 30 degrees. These results suggest that the pinning by CDs is angle-dependent due to the flux line structure with strong line tension around B parallel to ab: CDs around the ab-plane can trap flux lines along their long axis only in much narrower angular-range, in comparison with CDs around the c-axis.