Surfactant enhanced antiferromagnetic coupling in magnetron sputtered Cu/Co multilayers: A neutron reflectivity study

TL;DR

This study demonstrates that using Ag surfactant in Cu/Co multilayers improves interface symmetry, significantly enhances antiferromagnetic coupling and magnetoresistance, and reveals a correlation between interface roughness and spin-dependent scattering.

Contribution

It introduces the use of Ag surfactant to control interface roughness and enhance magnetic coupling in Cu/Co multilayers, providing new insights into interface effects.

Findings

Ag surfactant balances surface free energy, leading to symmetric interfaces.

Symmetric interfaces significantly increase antiferromagnetic coupling and magnetoresistance.

Increased interface roughness reduces spin-dependent scattering.

Abstract

In this work we studied Cu/Co multilayers prepared using dc-magnetron sputtering technique with Ag surfactant. It was found that Ag balances the difference in the surface free energy of Cu and Co and this results in removing the asymmetry in the interface roughness of Cu-on-Co and Co-on-Cu interfaces. As the interfaces become symmetric, we observe a significant enhancement in antiferromagnetic coupling and magneto resistance. Further, a correlation of spin-dependent scattering with the interface roughness is brought by comparing Cu/Co multilayer prepared using different deposition methods. It was found that as interface roughness increases spin-dependent scattering decreases.