Magnetic skyrmionium diode with a magnetic anisotropy voltage gating

The magnetic skyrmionium can be seen as a coalition of two magnetic skyrmions with opposite topological charges and has potential applications in next-generation spintronic devices. Here, we report the current-driven dynamics of a skyrmionium in a ferromagnetic nanotrack with the voltage-controlled magnetic anisotropy. The pinning and depinning of a skyrmionium controlled by the voltage gate are investigated. The current-driven skyrmionium can be used to mimic the skyrmionium diode effect in the nanotrack with a voltage gate. We have further studied the skyrmionium dynamics in the nanotrack driven by a magnetic anisotropy gradient in the absence of spin current. The performance of a single wedge-shaped voltage gate at different temperatures is studied. Our results may provide useful guidelines for the design of voltage-controlled and skyrmionium-based spintronic devices.

This work was supported by the State Key Program for Basic Research of China (Grant No. 2016YFA0300803), the National Natural Science Foundation of China (Grant Nos. 61427812 and 11574137), the Jiangsu Natural Science Foundation (Grant No. BK20140054), the Jiangsu Shuangchuang Team Program, and the UK EPSRC (No. EP/G010064/1). X.Z. acknowledges the support from the National Natural Science Foundation of China (Grant No. 12004320) and the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2019A1515110713). Y.Z. acknowledges the support from the President's Fund of CUHKSZ, Longgang Key Laboratory of Applied Spintronics, National Natural Science Foundation of China (Grant Nos. 11974298 and 61961136006), Shenzhen Key Laboratory Project (Grant No. ZDSYS201603311644527), and Shenzhen Peacock Group Plan (Grant No. KQTD20180413181702403).