Critical current density of YBa 2Cu 3O y containing inclined columnar defects

Abstract

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 YBa 2Cu 3O y (YBCO) thin film after the irradiation with 200 MeV Au ions from the direction θ irr=45° off the c-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 φ , the contribution of the columnar defects to the pinning force per unit volume, ΔF p, increases monotonically. The peak field for ΔF p as a function of the magnetic field seems to be almost independent on B φ .