Voltage controlled memory device based on fixed magnetic skyrmions*

Manipulating static magnetic skyrmions with voltage control of magnetic anisotropy (VCMA) can be utilized to design energy efficient memory devices with reduced device footprint. Using micromagnetic simulation, we demonstrate such devices. With application of a sequential positive and negative voltage pulse, two skyrmionic (core-up and core-down) and two ferromagnetic (up and down) states can be achieved [1]. Further, starting from a ferromagnetic state, a voltage pulse that reduces PMA can induce reversal via skyrmion breathing [2]. As a proof of concept experiment, we demonstrate such VCMA induced manipulation of magnetic skyrmions in an antiferromagnet/ferromagnet/oxide heterostructure film. We observed annihilation of skyrmions while increasing PMA and formation of more skyrmions by reducing PMA. This reversible creation and annihilation of skyrmions could potentially lead to novel skyrmion based memory devices.
1. Sci. Rep., 6, 31272, 2016.
2. ACS Appl Mat. Inter. 10 (20), pp 17455–17462, 2018.