Magnetic instability in both ultrapure and carbon-doped MgB 2 films is investigated by magneto-optical imaging, transport, and bulk magnetization measurements. In the carbon-doped MgB 2 thin films, familiar dendritic flux-jump patterns were observed at low temperature as reported in previous experiments. In the ultrapure MgB 2 thin film, however, a remarkably stable flux penetration was observed, clearly showing the classic behavior of the critical state model. Such different behavior indicates that the electron scattering ultimately controls the magnetic stability of the MgB 2 films.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)