### Abstract

A macroscopic observation of a magnetic flux distribution on the surface of a superconducting bulk material was performed. First, a single-domained thin rectangular YBCO sample (10 mm×10mm×1mm) was field-cooled in liquid nitrogen. After the applied field was turned off, a field distribution in the area of 10mm×10mm was mapped by scanning the sample surface at intervals of 0.5mm using a Hall probe fixed to a XY-stage. The obtained field distribution was visualized into a three-dimensional distribution map and a two-dimensional contour graph. The overall shape of the field distribution had a four-fold symmetry reflected by the sample geometry. Next, assuming that the critical current density J_{c} is independent of the field strength, a field distribution generated by square current loops was calculated numerically. The intragranular J_{c} was estimated to be 2.6×10^{4}A/cm^{2} (77K, OT) by fitting the calculated profile to the measured profile. Finally, it is found that the measurement of field distributions on the surface of a superconductor using a Hall probe is applicable to an estimation of an intragranular J_{c} for a superconductor without destroying the samples.

Original language | English |
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Pages (from-to) | 1818-1821 |

Number of pages | 4 |

Journal | IEEE Transactions on Applied Superconductivity |

Volume | 5 |

Issue number | 2 pt 2 |

Publication status | Published - 1995 Jun |

Externally published | Yes |

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### ASJC Scopus subject areas

- Electrical and Electronic Engineering
- Physics and Astronomy (miscellaneous)

### Cite this

*IEEE Transactions on Applied Superconductivity*,

*5*(2 pt 2), 1818-1821.