Magneto-transport and magnetic textures in Ho/FeCoGd/\beta-W multilayers

TL;DR

This study investigates the magnetic and transport properties of Ho/FeCoGd/eta-W multilayers, revealing interface-driven Dzyaloshinskii-Moriya interactions that stabilize topological spin textures and influence Hall effects.

Contribution

It demonstrates the role of interfacial DMI in multilayers with 3d and 4f magnetic sublattices, showing topological Hall effects near magnetic compensation temperatures.

Findings

Presence of labyrinth domain spin textures with zero remanence.

Large negative anomalous Hall resistivity dominated by interfacial effects.

Topological Hall contribution linked to DMI in nearly compensated lattices.

Abstract

The enhancement of interfacial Dzyaloshinskii-Moriya Interaction (DMI) in magnetic multilayers results in the stabilization of topological spin textures like chiral domain walls and skyrmions. Here we report on the evaluation of interface-driven magnetic interactions in a uniquely designed multilayer where each magnetic layer of two AFM coupled sublattices of 3d and 4f moments is sandwiched between the layers of \beta-tungsten and holmium whose spin Hall angles are large but opposite in sign. The atomic and magnetic periodicity of these multilayers is established by polarized neutron reflectivity measurements and the presence of a labyrinth domain spin texture of zero remanence with x-ray photoelectron microscopy. Measurements of the Hall resistivity (\rho_{xy}(T, H)) together with static magnetization (M(T,H)) over a broad range of temperature (T) and magnetic field (H) indicate impending compensation between 3d and 4f sublattices at T>350 K. These multilayers are characterized by a small (0.04 %) but positive magnetoresistance indicative of interface enhance scattering and a large (40 n\Omega.m) and negative anomalous \rho_{xy}(T,H) which results from a parallel alignment of 4f moments with the external magnetic field. No distinct scaling is seen between \rho_{xy}(T,H), \rho_{xx}(T, H) and M(T,H) at temperatures above 200K where the magnetization develops out-of-plane anisotropy. The field scans of \rho_{xy} at T>200K show a distinct cusp in the vicinity of magnetic saturation. These Hall data have been analyzed in the framework of a model where a distinct topological contribution to \rho_{xy} rides over the anomalous Hall resistivities of the 3d and 4f magnetic sublattices. It is suggested that this apparent topological effect results from an interfacial DMI and dominates \rho_{xy}(T,H) in the temperature regime where the 3d and 4f lattices are nearly compensated.