Nondestructive ultrafast steering of a magnetic vortex by terahertz pulses

Dongxing Yu,Chenglong Jia,Jamal Berakdar,Jiyong Kang

doi:10.1038/s41427-020-0217-8

Dongxing Yu, Chenglong Jia + Show 2 more

Open Access

https://doi.org/10.1038/s41427-020-0217-8

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Abstract

Electric control of magnetic vortex dynamics in a reproducible way on an ultrafast time scale is a key element in the quest for efficient spintronic devices with low-energy consumption. To be useful, the control scheme should ideally be swift, be scalable, be noninvasive, and result in reliable magnetic switching. Such requirements, particularly the reproducibility of altering the vortex chirality and/or polarity, are not yet met by magnetic vortex switching via external magnetic fields, spin-polarized currents, spin waves, or laser pulses. Here, we demonstrate a novel packaged-skyrmion-mediated vortex switching process driven by a simple sequence of picosecond electrical field pulses via magnetoelectric interactions. Both the vortex chirality and polarity show a well-defined reversal behavior. The unambiguous repeated switching between four different magnetic vortex states provides an energy-efficient, highly localized, and coherent control method for nonvolatile magnetic vortex-based information storage and handling.

Highlights

Magnetic vortices are formed in confined soft ferromagnetic structures, such as disks, triangles, squares, and stripes on the micron/submicron scales[1,2]
The driving force is a subtle competition between the exchange interaction and shape anisotropy in confined geometries
While few studies considered the simultaneous control of the vortex chirality and polarity, it turned out to be challenging to precisely determine when core switching occurs, and even worse, the clockwise and counterclockwise vortex states may randomly emerge with a similar occurrence frequency[13], largely prohibiting the development of reliable magnetic vortexbased spintronics. To remedy this situation and facilitate the vortex dynamics for ultrafast all-optical magnetism[15], in this work, we exploit another feature of noncollinear spin ordering, namely, the magnetoelectric (ME) effect leading to a spin-driven emergent ferroelectric polarization P, which allows an external THz electric-field E(t, r) to couple with and drive the vortex via −E·P

Summary

Introduction

Magnetic vortices are formed in confined soft ferromagnetic structures, such as disks, triangles, squares, and stripes on the micron/submicron scales[1,2]. To remedy this situation and facilitate the vortex dynamics for ultrafast all-optical magnetism[15], in this work, we exploit another feature of noncollinear spin ordering, namely, the magnetoelectric (ME) effect leading to a spin-driven emergent ferroelectric polarization P, which allows an external THz electric-field E(t, r) to couple with and drive the vortex via −E·P.

Results

Conclusion