Strain-induced polarity switching of magnetic vortex in Fe1−xGax alloys with different compositions

Abstract

The strain-induced polarity switching of magnetic vortex in the Fe1−xGax nanodots with different compositions is demonstrated by a real-space phase-field model, which explicitly includes the cross-coupling between magnetization and mechanical strain. The composition of Fe1−xGax nanodots has significant influence on the critical shear strain that induces the polarity switching of magnetization vortex. The critical shear strain in the Fe71Ga29 nanodot is one order of magnitude smaller than that of the Fe19Ga81 nanodot, which makes the polarity switching much easier under a mechanical shear strain. In addition, we elucidate that both the magnetostrictive coefficient and exchange stiffness that changes with compositions play the decisive role in the critical behavior; the higher magnetostrictive coefficient (or lower exchange stiffness) decreases critical shear strain.