Spin pumping and interlayer exchange coupling through palladium

TL;DR

This study examines how palladium, a strongly Stoner-enhanced non-magnetic substrate, influences spin pumping and exchange coupling between ultrathin ferromagnetic films, revealing significant effects on magnetic interactions and their oscillatory behavior.

Contribution

It demonstrates the impact of substrate Stoner enhancement on interlayer exchange coupling and spin pumping, providing new insights into magnetic interactions through palladium.

Findings

Interlayer exchange coupling is suppressed by Stoner enhancement.

Spin pumping rate is mildly affected but detectable.

Oscillatory RKKY behavior is strongly suppressed by Stoner enhancement.

Abstract

The magnetic behaviour of ultrathin ferromagnetic films deposited on substrates is strongly affected by the properties of the substrate. We investigate the spin pumping rate, interlayer exchange coupling and dynamic exchange coupling between ultrathin ferromagnetic films through palladium, a non-magnetic substrate that displays strong Stoner enhancement. We find that the interlayer exchange coupling, both in the static and dynamic versions, is qualitatively affected by the substrate's Stoner enhancement. For instance, the oscillatory behavior that is a hallmark property of the RKKY exchange coupling is strongly suppressed by Stoner enhancement. Although the spin pumping rate of ferromagnetic films atop palladium is only mildly changed by Stoner enhancement the change is large enough to be detected experimentally. The qualitative aspects of our results for palladium are expected to remain valid for any non-magnetic substrate where Coulomb repulsion is large.