Flux Pinning Properties of Bi,Pb2223 Films With Columnar Defects by Xe Irradiation

High-quality Hfand Zr-doped Bi,Pb2223 films on SrTiO
₃
substrate were fabricated by RF magnetron sputtering and two-step annealing. In order to investigate flux pinning properties of columnar defects, Xe-ions were irradiated onto the Hfand Zr-doped Bi,Pb2223 films along the c-axis. Although the critical temperature T
_c
was decreased by heavy ions irradiation, the infield critical current density J
_c
in the magnetic field parallel to the c-axis was increased drastically. The enhancement of Jc was achieved in a wide range of magnetic fields over the matching magnetic field B
_φ
. In the angular dependence of J
_c
, the improvement of J
_c
was observed in almost all angle region of magnetic field orientation except for the vicinity of the ab-plane. However, the peak centered at the c-axis did not appear in the angular dependence of J
_c
. This behavior was quite different from REBa
₂
Cu
³
O
_y
films installed columnar defects. The angular dependences of J
_c
in the Hfand Zr-doped Bi,Pb2223 films were determined by the magnetic field component along the c-axis. These results are originated from the strong two-dimensional nature of the Bi,Pb2223 film.