Experimental creation and annihilation of nonvolatile magnetic skyrmions using voltage control of magnetic anisotropy without an external magnetic field

TL;DR

This paper demonstrates voltage-controlled creation and annihilation of magnetic skyrmions in heterostructures without external magnetic fields, offering a promising approach for energy-efficient skyrmion-based memory devices.

Contribution

It introduces a novel method to manipulate skyrmions using voltage-controlled magnetic anisotropy without external magnetic fields, supported by experimental and simulation results.

Findings

Skyrmions can be annihilated or created by voltage pulses that modulate magnetic anisotropy.

Skyrmions are stabilized without external magnetic fields due to exchange bias.

Voltage control enables reversible skyrmion manipulation in heterostructures.

Abstract

In this work, we utilize voltage controlled magnetic anisotropy (VCMA) to manipulate magnetic skyrmions that are fixed in space. Memory devices based on this strategy can potentially be of smaller footprint and better energy efficiency than current-controlled motion-based skyrmionic devices. To demonstrate VCMA induced manipulation of skyrmions, we fabricate antiferromagnet/ferromagnet/oxide heterostructure films where skyrmions can be stabilized without any external magnetic field due to the presence of exchange bias. These isolated skyrmions were annihilated by applying a voltage pulse that increased PMA. On the other hand, decreasing PMA promoted formation of more skyrmions. Furthermore, skyrmions can be created from chiral domains by increasing PMA of the system. To corroborate our experimental observations, we performed micromagnetic simulation. The proposed method could potentially lead to novel skyrmion-based memory devices.