Voltage Control of magnetic Skyrmions in patterned nanodots*

Manipulation of magnetic skyrmions that are fixed in space can lead to the implementation of computing devices with smaller footprint. Moreover, if the control is achieved solely via applying an electric field, additional advantage of energy efficiency can be obtained. We have previously shown the feasibility of such a scheme by annihilating and creating skyrmions in a thin film of IrMn/CoFeB/MgO using Voltage Control of Magnetic Anisotropy (VCMA) [1]. However, in patterned structures, due to the confinement effect, complete reversal of skyrmion polarity as well as skyrmion mediated ferromagnetic reversal can be achieved using only voltage pulses [2, 3]. Here we propose to show this behavior in patterned nanodots of CoFeB sandwiched between an oxide and a heavy metal layer. We will also study the intermediate magnetic states during the reversal by performing magnetic force microscopy (MFM) imaging under in situ voltage. Finally, micromagnetic simulations will be presented that corroborate our experimental observations.
[1] Bhattacharya et al arxiv, 1904.00701 (2019).
[2] Bhattacharya et al, Appl. Mat. Interfaces, 10 (20), 17455-17462 (2018).
[3] Bhattacharya et al, Sci Rep., 6, 31272 (2016).