The Magnetic Microstructure and Flux Dynamics of High T sub c Superconductors.
01 January 1987
We present high resolution Bitter patterns which reveal the magnetic microstructure of the high T sub c superconductor Ba sub 2 YCu sub 3 0 sub 7, allowing the direct observation of vortices, and their response to magnetic field changes. By forming patterns in the presence of a time-varying magnetic field, or a transport current, we also study the dynamics of flux motion. Our results reveal a hierarchy of pinning sites and a remarkable anisotropy in the characteristics of neighboring twins, and allow the mapping of superconducting regions in the presence of circulating and transport currents.