Increased lifetime of metastable skyrmions by controlled doping

Abstract

Metastable magnetic skyrmions possess a nonzero temperature-dependent lifetime, which poses an obstacle for their application in devices. Here, the authors show that, for skyrmions in Cu${}_{2}$OSeO${}_{3}$, a small quantity of Zn substitution significantly increases this lifetime, dramatically reducing the cooling rate required to create a substantial metastable population. Time-resolved AC magnetometry measurements suggest that the effect is due to an increase in the pinning-site density that leads to slowing-down the unwinding of the skyrmion lattice, rather than to an alteration of the energy barrier.