Magnetic skyrmions probed and manipulated by spin-polarized scanning tunneling microscopy: Efficient spin switching

Session Information

Location: amf. P7 | "Gheorghe Asachi" Technical University of Iași (TUIAȘI)
Day: 2. Tuesday 16
Time: 12:10-12:30
Chairperson: Teodora Kirova

Presentation Details

Presentation Type: Oral presentation
Title: Magnetic skyrmions probed and manipulated by spin-polarized scanning tunneling microscopy: Efficient spin switching
Abstract: Spin-polarized scanning tunneling microscopy (SP-STM) is a very useful tool to obtain atomic-scale information on real-space complex spin textures at material surfaces [1,2]. Moreover, by locally applying current pulses with the SP-STM tip the controlled manipulation of individual magnetic skyrmions have been demonstrated [3]. The effect of the spin transfer torque (STT) of the tunneling electrons [4] responsible for the magnetic switching and manipulation of magnetic skyrmions is analyzed. For our theoretical investigation metastable skyrmionic spin structures with various topological charges ranging from Q = -3 to +2 in the (Pt0.95Ir0.05)/Fe/Pd(111) ultrathin magnetic film are considered. We find that the STT efficiency (torque/current) acting on the spins of the skyrmions can reach large values up to 25 million meV/A, but they dramatically vary between large and small values depending on the lateral position of the SP-STM tip above the topological spin textures [5]. A simple expression for the STT efficiency is introduced to explain its variation. Our results are expected to guide SP-STM experiments to select SP-STM tip positions for an efficient switching of the skyrmionic structures by localized tunneling STT. Furthermore, our calculated spin transport vectors can be used for the investigation of tunneling-current-induced spin dynamics of topologically distinct surface magnetic skyrmionic textures.

References:
[1] N. Romming et al. Phys. Rev. Lett. 114, 177203 (2015).
[2] K. Palotás et al. Phys. Rev. B 96, 024410 (2017).
[3] N. Romming et al. Science 341, 636 (2013).
[4] K. Palotás et al. Phys. Rev. B 97, 174402 (2018). K. Palotás, Phys. Rev. B 98, 094409 (2018).
[5] K. Palotás et al. J. Magn. Magn. Mater. 519, 167440 (2021).

Presenter

Dr Krisztian Palotas
HUN-REN Wigner Research Center for Physics | Hungary

Authors

1. Palotas, Krisztian | Quantum Materials Research Group, HUN-REN Wigner Research Center for Physics, H-1121, Budapest, Hungary