Imaging of magnetic flux distribution in vicinity of insulating particles in high-Tc superconductor by electron holography.

REBaCuO (RE: rare earth) bulk superconductors, whose microstructures can be controlled by quench and melt growth (QMG) processing, have a high critical current density Jc, which makes them well suited for use in practical applications. Through a combination of electron holography and a focused ion-beam technique, we succeeded in visualizing a fluxon pinned by an insulating particle in a QMG bulk Y-Ba-Cu-O superconductor. We also clarified the magnetic flux distribution in the vicinity of the insulating particles at different temperatures in a uniform external magnetic field. [ABSTRACT FROM AUTHOR]