Electron scattering dependence of dendritic magnetic instability in superconducting MgB2 films

TL;DR

This study investigates how electron scattering influences magnetic stability in MgB2 superconducting films, revealing that doping and purity levels significantly affect flux behavior and stability.

Contribution

It demonstrates that electron scattering determines magnetic stability in MgB2 films, contrasting dendritic flux jumps in doped samples with stable flux in ultra-pure samples.

Findings

Dendritic flux jumps observed in carbon-doped MgB2 films.

Stable flux penetration consistent with the critical state model in ultra-pure MgB2.

Electron scattering controls magnetic stability in MgB2 superconducting films.

Abstract

Magnetic instability in both ultra-pure and carbon-doped MgB2 films is investigated by magneto-optical imaging, transport and bulk magnetization measurements. In the carbon-doped MgB2 thin film, familiar dendritic flux-jump patterns were observed at low temperature as reported in previous experiments. In the ultra-pure MgB2 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 MgB2 films.