Interfacial coupling across a modified interface studied with ferromagnetic resonance

TL;DR

This study investigates how a gold dusting layer affects the interfacial exchange coupling and magnetisation in a NiFe/IrMn film using ferromagnetic resonance and simulations, revealing uniform coupling and orientation-dependent magnetisation states.

Contribution

It provides new insights into how gold dusting modifies interfacial magnetic properties and coupling in exchange-biased films, combining experimental FMR data with a discretised simulation model.

Findings

Exchange coupling remains relatively uniform with increasing gold thickness.

A sudden drop in exchange coupling occurs at 1.5 Å of gold.

Interface magnetisation decreases with gold dusting thickness and depends on ferromagnet alignment.

Abstract

Using spin waves we directly probe the interface of an exchange biased Ni$_{80}$Fe$_{20}$/Ir$_{25}$Mn$_{75}$ film which has been modified by the presence of an Au dusting layer. Combining this experimental data with a discretised simulation model, parameters relating to interface exchange coupling and modification of interface magnetisation are determined. Exchange coupling is found to be relatively uniform as gold thickness is increased, and undergoes a sudden drop at 1.5$\textrm{\AA}$ of gold. Interface magnetisation decreases as a function of the gold dusting thickness. Antiparallel alignment of the ferromagnet and antiferromagnet supress the interface magnetisation compared to when they are in parallel alignment. These findings imply that the interface region has specific magnetisation states which depend on the ferromagnet orientation.