Voltage control of skyrmions: creation, annihilation and zero-magnetic field stablization

TL;DR

This study demonstrates voltage-controlled creation, annihilation, and stabilization of skyrmions in a heterostructure, highlighting potential for low-energy spintronic devices through magnetic anisotropy manipulation.

Contribution

It provides experimental evidence of voltage effects on skyrmions, including zero-field stabilization, and combines measurements with micromagnetic simulations to understand underlying mechanisms.

Findings

Voltage can both enhance and deplete skyrmion density.

Zero magnetic field skyrmion stabilization achieved with voltage.

Voltage effects occur on a seconds timescale, indicating magnetic anisotropy control.

Abstract

Voltage manipulation of skyrmions is a promising path towards low-energy spintronic devices. Here, voltage effects on skyrmions in a GdOx/Gd/Co/Pt heterostructure are observed experimentally. The results show that the skyrmion density can be both enhanced and depleted by the application of an electric field, along with the ability, at certain magnetic fields to completely switch the skyrmion state on and off. Further, a zero magnetic field skyrmion state can be stablized under a negative bias voltage using a defined voltage and magnetic field sequence. The voltage effects measured here occur on a few-second timescale, suggesting an origin in voltage-controlled magnetic anisotropy rather than ionic effects. By investigating the skyrmion nucleation rate as a function of temperature, we extract the energy barrier to skyrmion nucleation in our sample. Further, micromagnetic simulations are used to explore the effect of changing the anisotropy and Dzyaloshinskii-Moriya interaction on skyrmion density. Our work demonstrates the control of skyrmions by voltages, showing functionalities desirable for commercial devices.