Symmetry breaking in spin spirals and skyrmions by in-plane and canted magnetic fields

L Schmidt,J Hagemeister,R Wiesendanger,K Von Bergmann,A Kubetzka,P-J Hsu

doi:10.1088/1367-2630/18/7/075007

Abstract

The influence of in-plane and canted magnetic fields on spin spirals and skyrmions in atomic bilayer islands of palladium and iron on an Ir(111) substrate is investigated by scanning tunneling microscopy at low temperatures. It is shown that the spin spiral propagation direction is determined by the island’s border which can be explained by equilibrium state calculations on a triangular lattice. We find a different response of spin spirals to in-plane magnetic fields for a propagation direction parallel to the applied field as compared to perpendicular, which originates from their cycloidal nature. As a result, the spin spiral propagation direction may be reorientated by in-plane fields. Furthermore, it is demonstrated that also skyrmions are distorted in canted fields which allows to determine the sense of magnetization rotation as enforced by the interfacial Dzyaloshinskii–Moriya interaction.

Highlights

Ultrathin magnetic films on heavy metal substrates can exhibit complex spin textures due to the competition of Heisenberg exchange interaction, magnetocrystalline anisotropy, and Dzyaloshinskii–Moriya interaction (DMI) [1]
The observed change in dI/dV is similar to the one for the spin spirals: again, the dI/dV signal changes according to the orientation of the spin structure relative to the direction of the applied magnetic field, and we find the strongest change in the in-plane regions
The observed asymmetry directly reveals in which direction the in-plane parts of the skyrmion, that are collinear to the applied field, are pointed and—in combination with the orientation of the applied field’s out-of-plane component—we can derive the perpendicular orientation of the magnetic moments in the center of the skyrmion and its surrounding (compare figure 5(e))

Summary

July 2016

L Schmidt, J Hagemeister, P-J Hsu, A Kubetzka, K von Bergmann and R Wiesendanger. Keywords: spin spirals, skyrmions, magnetic vector-field response, ultrathin films, interfacial Dzyaloshinskii–Moriya interaction, scanning tunneling microscopy Supplementary material for this article is available online. Any further distribution of this work must maintain islands of palladium and iron on an Ir(111) substrate is investigated by scanning tunneling microscopy attribution to the at low temperatures. It is shown that the spin spiral propagation direction is determined by the island’s author(s) and the title of the work, journal citation border which can be explained by equilibrium state calculations on a triangular lattice. Different response of spin spirals to in-plane magnetic fields for a propagation direction parallel to the applied field as compared to perpendicular, which originates from their cycloidal nature. The spin spiral propagation direction may be reorientated by in-plane fields. It is demonstrated that skyrmions are distorted in canted fields which allows to determine the sense of magnetization rotation as enforced by the interfacial Dzyaloshinskii–Moriya interaction

Introduction

Spin spirals in in-plane magnetic fields

Skyrmions in canted magnetic fields

Conclusion