Dendritic flux instability in MgB2 films above liquid hydrogen temperature.

Magnetic flux instability limits potential applications of superconductors such as MgB₂ in practical devices. Previous studies in MgB₂ films exposed to magnetic fields revealed the occurrence of dendritic flux avalanches at temperatures below T ∼ 10 K. In the present work it is shown that films of MgB₂ exposed to a fast-ramped magnetic field display a dendritic flux instability at elevated temperatures, up to 23 K. Such instability can therefore cause malfunctioning of practical devices based on MgB₂ films even when operating at liquid hydrogen temperature. [ABSTRACT FROM AUTHOR]