Direct writing of room temperature and zero field skyrmion lattices by a scanning local magnetic field

Abstract

Magnetic skyrmions are topologically protected nanoscale spin textures exhibiting fascinating physical behaviors. Recent observations of room temperature skyrmions in sputtered multilayer films are an important step towards their use in ultra-low power devices. Such practical applications prefer skyrmions to be stable at zero magnetic fields and room temperature. Here, we report the creation of skyrmion lattices in Pt/Co/Ta multilayers by a scanning local field using magnetic force microscopy tips. We also show that those newly created skyrmion lattices are stable at both room temperature and zero fields. Lorentz transmission electron microscopy measurements reveal that the skyrmions in our films are of Néel-type. To gain a deeper understanding of the mechanism behind the creation of a skyrmion lattice by the scanning of local fields, we perform micromagnetic simulations and find the experimental results to be in agreement with our simulation data. This study opens another avenue for the creation of skyrmion lattices in thin films.

Individual skyrmion manipulation by local magnetic field gradients

“…While MFM is well established as a tool to measure DMI and investigate nanoscale magnetic skyrmions in Co-based multilayer stacks 17,42,[44][45][46] , similar studies for CoFeB-based systems have involved using less widely available techniques, such as Scanning Transmission X-ray Microscopy (STXM) 16,18,26,27 , Magnetic Transmission soft X-ray Microscopy (MTXM) 16,19 or X-ray holography 25 . MFM imaging of soft magnetic materials like CoFeB can actually be very challenging due to image deformations caused by the probe-sample magnetic interaction.…”

Thermal creation of skyrmions in ferromagnetic films with perpendicular anisotropy and Dzyaloshinskii-Moriya interaction

“…Small skyrmions can be also written and deleted in a controlled fashion with local spin-polarized currents from a scanning tunneling microscope 59 . With a tip of a scanning magnetic force microscope (MFM), one can cut stripe magnetic domains into skyrmions 60 . It has been suggested that individual skyrmions can also be written with an MFM tip 61 .…”

Helicity of magnetic vortices and skyrmions in soft ferromagnetic nanodots and films biased by stray radial fields

“…Such kind of fields can be, obviously, created in other ways. For example, the stray fields of radial symmetry can be created by the tip of a magnetic force microscope, resulting in the observation of unconventional vortices in soft magnetic dots, which, however, disappear as soon as the tip is removed [45][46][47].…”