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

Abstract

High-quality Hf- and Zr-doped Bi,Pb2223 films on SrTiO3 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 Hf- and Zr-doped Bi,Pb2223 films along the c -axis. Although the critical temperature Tc was decreased by heavy ions irradiation, the in-field critical current density Jc 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 Bφ . In the angular dependence of Jc , the improvement of Jc 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 Jc . This behavior was quite different from REBa2Cu3O y films installed columnar defects. The angular dependences of Jc in the Hf- and 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.