Strain-mediated voltage-controlled switching of magnetic skyrmions in nanostructures. (December 2018)

• Record Type: Journal Article
• Authors: Hu, Jia-Mian; Yang, Tiannan; Chen, Long-Qing
• Is Part Of: Npj computational materials. Volume 4:issue 1(2018)
• Page Start: 1
• Page End: 7
• Publication Date: 2018-12
• Subjects: Materials science -- Computer simulation -- Periodicals; Materials science -- Mathematical models -- Periodicals; Materials science -- Computer simulation; Electronic journals; Periodicals; 620.110285
• DOI: 10.1038/s41524-018-0119-2
• Languages: English
• ISSNs: 2057-3960

Abstract

Abstract Magnetic skyrmions are swirling spin structures stabilized typically by the Dyzaloshinskii-Moriya interaction. The existing control of magnetic skyrmions has often relied on the use of an electric current, which may cause overheating in densely packed devices. Here we demonstrate, using phase-field simulations, that an isolated Néel skyrmion in a magnetic nanodisk can be repeatedly created and deleted by voltage-induced strains from a juxtaposed piezoelectric. Such a skyrmion switching is non-volatile, and consumes only ~0.5 fJ per switching which is about five orders of magnitude smaller than that by current-induced spin-transfer-torques. It is found that the strain-mediated skyrmion creation occurs through an intermediate vortex-like spin structure, and that the skyrmion deletion occurs though a homogenous shrinkage during which the Néel wall is temporarily transformed to a vortex-wall. These findings are expected to stimulate experimental research into strain-mediated voltage control of skyrmions, as well as other chiral spin structures for low-power spintronics. Spintronics: strain-mediated voltage control of magnetic skyrmions Isolated magnetic skyrmions can be created and deleted in a multilayer magnetic nanostructure by voltage-induced strains from the underlying piezoelectric layer. A team led by Long-Qing Chen from the Pennsylvania State University carried out phase-field simulations on an integrated multilayer, where a magnetic ultrathin nanodisk is sandwiched by a capping layer and a heavy-metal layer. They consider a net Dyzaloshinskii-Moriya interaction arising only from the magnet/heavy-metal interface, so that a Néel skyrmion is more favorable than a Bloch skyrmion. They demonstrate that the voltage-induced strain alone can drive non-volatile switching from a ferromagnetic state to a skyrmion and vice versa, without using magnetic fields. These results may stimulate experimental efforts in realizing strain-mediated voltage control of skyrmions, as well as other spin structures for low-power spintronics.