Antisymmetric magnetoresistance and helical magnetic structure in compensated Gd/Co multilayer

TL;DR

This study reveals a twisted helical magnetic structure with planar 2π domain walls and correlated magnetic inhomogeneities in Gd/Co multilayers, which influence antisymmetric magnetoresistance and could impact spintronic applications.

Contribution

It demonstrates the formation of planar 2π domain walls and correlated magnetic inhomogeneities in Gd/Co multilayers using polarized neutron reflectivity, revealing new magnetic structures and behaviors.

Findings

Formation of planar 2π domain walls below TComp

Development of correlated magnetic inhomogeneities in Gd layers

Antisymmetric magnetoresistance linked to magnetic roughness

Abstract

Using spin dependent specular and off-specular polarized neutron reflectivity (PNR), we report the observation of a twisted helical magnetic structure with planar 2{\pi} domain wall (DW) and highly correlated magnetic domains in a Gd/Co multilayer. Specular PNR with polarization analysis reveals the formation of planar 2{\pi}DWs below a compensation temperature (TComp), resulting to positive exchange bias in this system. Off-specular PNR with spin polarization showed development of magnetic inhomogenities (increase in magnetic roughness) for central part (thickness ~ 25-30 {\AA}) of each Gd layer, where magnetization is aligned perpendicular (in-plane) to an applied field. These magnetic roughness are vertically correlated and results into Bragg sheet in spin flip channel of Off-specular PNR data, which is contributing towards an antisymmetric magnetoresistance at TComp in the system. The growth and tunability of highly correlated magnetic inhomogeneities (roughness) and domain structure around TComp in combination of twisted helical magnetic structure with planar 2{\pi}DWs will be key for application in all-spin-based technology.