Critical Current Density of Skyrmions through a Voltage Gate in a Synthetic Antiferromagnetic Nanotrack Manipulated by Local Voltage-Controlled Magnetic Anisotropy.

Skyrmions are considered to be ideal information carriers for next-generation low-power spintronic devices, and local voltage-controlled magnetic anisotropy (VCMA) provides an effective means for their manipulation. Here, we report the dynamics of a current-driven skyrmion passing through a local gradient VCMA region in a synthetic antiferromagnetic nanotrack. Utilizing analysis of dynamic results combined with the Thiele equation, we have established formulas for the critical current density (Jc) required for skyrmions to pass through the local VCMA region. The Jc values calculated using the formulas match well with those obtained from micromagnetic simulations. Regardless of whether the skyrmion passes through the voltage gate in the forward or reverse direction, the gradient in the variable perpendicular magnetic anisotropy region dominates the Jc. This work reveals the transport characteristics of skyrmions under local VCMA modulation and a method for manipulating the moving behavior of skyrmions, providing theoretical guidance for the design of low-power spintronic devices based on skyrmions.