Suppressed flux motion in magnesium diboride films

The mixed-state transport behavior of magnesium diboride films shows a suppression of flux motion that is more severe than is typical for conventional vortex pinning. At currents approaching the pair-breaking value and magnetic fields approaching the upper-critical field, the conductance diverges and the current-resistance and temperature-conductance curves become parallel, showing mainly a shift in the transition due to pairbreaking with minimal signs of flux motion.