## Abstract

A study of the DC I-V curves of BSCCO tapes exposed to AC perpendicular and parallel magnetic fields is presented. AC magnetic fields with amplitudes up to 700 G and frequencies from 1 to 430 Hz have been applied perpendicular and parallel to tapes carrying DC currents at T = 77 K. Both field orientations result in a significant DC electric field increase, in comparison to applying DC magnetic fields of the same intensity. However, the observed I-V curves behavior is different for the perpendicular and parallel cases. In the perpendicular case, we distinguish between two frequency regimes: for frequencies above 40 Hz, the observed I-V curves obey the empirical power law dependence with current density, J_{C}, and power index, n, that strongly depend on the field amplitude. For frequencies below 20 Hz, the observed I-V curves deviate from power law description. In the parallel field case, the I-V curve can be regarded as a superposition of an additional DC voltage over the no field I-V curve. This additional voltage increases with increasing current, peaks near the critical current and decreases thereafter. The results are discussed assuming a narrowing down of the DC current path under the application of a perpendicular AC field. Shaking of the pinned vortices under the application of a parallel AC field is assumed for explaining the results in this case.

Original language | English |
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Pages (from-to) | 2891-2894 |

Number of pages | 4 |

Journal | IEEE Transactions on Applied Superconductivity |

Volume | 15 |

Issue number | 2 PART III |

DOIs | |

State | Published - Jun 2005 |

### Bibliographical note

Funding Information:Manuscript received October 5, 2004. This work was supported in part by the Israeli Ministry of Infrastructure. The authors are with the Institute of Superconductivity, Department of Physics, Bar-Ilan University Ramat-Gan 52900, Israel (e-mail: freidma@mail.biu.ac.il). Digital Object Identifier 10.1109/TASC.2005.848256 Fig. 1. Magnetic flux lines inside the tape for AC field magnetic field perpendicular to broad side of the tape. w is the width of the tape and b is a width of the central zone free of AC field.

## Keywords

- Ac field
- Bi-2223 tape
- Critical current
- I-v curve. © 2005 ieee