Curvature-induced enhancement of thermal stability of skyrmions

Abstract

Geometry plays an important role in the nucleation, stabilization, and manipulation of magnetization patterns within magnetic nanoelements. This work analyzes the impact of curvature on the thermal stability of skyrmions hosted on Gaussian-shaped nanoshells. Based on annihilation processes observed in flat nanoparticles, three distinct annihilation processes—skyrmion contraction, expansion, and displacement toward the nanodot border—are analyzed. We show that curvature-induced effective interactions significantly alter the energy barriers associated with these annihilation processes. The changes in energy are related to the relative alignment between the skyrmion core and the direction normal to the surface, highlighting the presence of favorable and unfavorable chiralities for skyrmion stabilization in curved nanodots. We also show that, unlike the one obtained for flat nanodots, where the skyrmion lifetimes typically span seconds, the lowest energy barrier values in curved nanodots reach values that ensure skyrmion lifetimes at room temperature to months before thermal fluctuations annihilate them. Curvature parameters can control the annihilation mechanism. This enhancement in skyrmion stability holds even without external additional stimuli. This underscores the profound impact of curvature on the dynamic behavior and thermal stability of skyrmions within magnetic nanoelements.