Critical current density of YBa2Cu3Oy containing inclined columnar defects

Effects of columnar defects on the critical current density have been investigated by the in situ measurement of current-voltage characteristics for a c-axis oriented YBa2Cu3Oy, (YBCO) thin film after the irradiation with 200 MeV Au ions from the direction theta (irr) = 45 degrees off the e-axis, The dependences of the critical current density, J(c) on the magnetic field, the magnetic field angle, and the density of columnar defects are discussed. With increasing the density of the columnar defects, B-phi the contribution of the columnar defects to the pinning force per unit volume, DeltaF(p), increases monotonically. The peak field for DeltaF(p) as a function of the magnetic field seems to be almost independent on B-phi. (C) 2001 Elsevier Science B.V. All rights reserved.