Controlling the creation/annihilation and distribution of magnetic skyrmions by manipulating an externally applied voltage

Abstract

Magnetic skyrmions are currently gaining attention owing to their potential to act as information carriers in spintronic devices. However, conventional techniques which rely on modulating the electric current to write or manipulate information using skyrmions are not energy efficient. Therefore, in this study, a Ta/Co–Fe–B/Ta/MgO junction that hosts a skyrmion was utilized to fabricate a device to investigate the effect of applying a voltage in the direction perpendicular to the film plane. Magneto-optical Kerr effect microscopy was performed in a polar configuration to observe the difference in the perpendicular magnetic anisotropy by observing the behavior of the magnetic domain structure and the skyrmions. Our findings suggest that voltage-induced magnetic domain structure modulation and the creation/annihilation of skyrmions are both possible. Furthermore, manipulation of skyrmions was realized by utilizing repulsive magnetic dipole interaction between the voltage-created skyrmion and skyrmion, exhibiting Brownian motion, outside the top electrode. Thus, our proposed method can enable controlling the creation and annihilation of skyrmions and their positions by manipulating the externally applied voltage. These findings can advance unconventional computing fields, such as stochastic and ultra-low-power computing.