Controlling magnetic skyrmions in co/graphene via electric field

Tuning Dzyaloshinskii-Moriya interactions by using electric fields to stabilize topological chiral magnetic structures, such as sigmoidons, is a key research strategy for realising low-power electronic devices. Based on density functional theory calculations, we elucidate the electric field control of the skyrmions size in Co/graphene. Effective exchange coupling and Dzyaloshinsky-Moriya interaction (DMI) parameters between different neighbors Ji and di at different electric fields are derived. Meanwhile, we show the evolution of skyrmions size of Co /graphene under different electric field through numerical calculations and extended NdJ model. The magnitude of the J is found to linearly decrease as a function of electric field intensity, while the efficiency of the electric field in controlling the induced interfacial DMI is relatively weak. Hence a positive electric field contributes to the formation of small stable skyrmions in Co/graphene, by reducing the exchange coupling J of Co and graphene rather than increasing the DMI in a general way. Our findings provide a fundamental groundwork for electrical manipulation to control the size of magnetic skyrmions.