Transport properties of dipole skyrmions in amorphous FeGd multilayers

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.