Transport properties of dipole skyrmions in amorphous FeGd multilayers

TL;DR

This study investigates the transport properties of dipole skyrmions in amorphous FeGd multilayers, revealing a unique resistivity signature associated with skyrmion lattice formation and domain wall reconfiguration.

Contribution

It provides experimental evidence and micromagnetic simulations linking resistivity anomalies to skyrmion lattice formation and domain wall dynamics in amorphous multilayers.

Findings

Skyrmion lattice phase causes a distinct resistivity signature.

Resistivity anomalies depend on field history protocols.

Micromagnetic simulations confirm domain wall reconfiguration as the cause.

Abstract

The transport response of dipole skyrmions in amorphous centrosymmetric Fe/Gd multilayer is investigated by temperature and field-dependent resistivity measurements collected in three current and magnetic field configurations. It is shown that a dipole skyrmion lattice phase may form at certain temperatures leading to a unique signature of the polar longitudinal resistivity. This signature differs from the conventional field-varying parabolic response associated with stripe phases, which transition to a disordered skyrmion phase under applied fields. Transport measurements under different field history protocols reveal that the anomaly in the polar longitudinal resistivity appears under specific field history reversal processes. Our experimental results are reproduced using micromagnetic simulations that show the anomaly in the polar longitudinal resistivity is related to a domain wall reconfiguration that occurs as the domain morphology transitions from disordered stripes to a skyrmion lattice under applied perpendicular fields.