Writing and storing information in an array of magnetic vortex nanodisks using their azimuthal modes

TL;DR

This paper demonstrates how azimuthal modes in magnetic vortex nanodisks can be used to switch vortex cores, enabling information storage in nanodisk arrays through rotating magnetic fields.

Contribution

It introduces a method to write and store information in nanodisk arrays by exploiting azimuthal modes and vortex core switching with rotating magnetic fields.

Findings

Perpendicular uniaxial anisotropy lowers azimuthal mode frequencies.

Phase diagram of field intensity vs. frequency was developed.

Vortex core switching enables multiple memory states.

Abstract

The switching of a vortex core of a single disk in an array of a multilayer system is investigated by micromagnetic simulation. We found that the perpendicular uniaxial anisotropy (PUA) decreases the frequencies of the azimuthal mode in disks with magnetic vortex configuration. We obtained a phase diagram of magnetic field intensity vs. frequency of the azimuthal mode, as a function of the value of perpendicular uniaxial anisotropy. We demonstrated that rotating magnetic fields (CW and CCW) with frequency equal to azimuthal modes can be used to switch the vortex core of single disks in a disk array. This allows obtaining different memory states with a single array of nanodisks, and therefore writing information through the application of rotating fields.