Giant magnetic enhancement in Fe/Pd films and its influence on the magnetic interlayer coupling

TL;DR

This study uses first principles calculations to reveal a giant magnetic enhancement in Fe/Pd films, significantly affecting magnetic interlayer coupling, with implications for understanding magnetic interactions beyond traditional RKKY models.

Contribution

It demonstrates the large magnetic enhancement effect in Fe/Pd films and its impact on interlayer coupling, highlighting quantum interference effects not captured by simple models.

Findings

Induced Pd magnetization decays as n^{-2.4} from Fe monolayer

Giant magnetic enhancement oscillates strongly due to interference

Magnetic coupling is predominantly ferromagnetic, influenced by Pd polarization

Abstract

The magnetic properties of thin Pd fcc(001) films with embedded monolayers of Fe are investigated by means of first principles density functional theory. The induced spin polarization in Pd is calculated and analyzed in terms of quantum interference within the Fe/Pd/Fe bilayer system. An investigation of the magnetic enhancement effects on the spin polarization is carried out and its consequences for the magnetic interlayer coupling are discussed. In contrast to {\it e.g.} the Co/Cu fcc(001) system we find a large effect on the magnetic interlayer coupling due to magnetic enhancement in the spacer material. In the case of a single embedded Fe monolayer we find aninduced Pd magnetization decaying with distance $n$ from the magnetic layer as ~$n^{-\alpha}$ with $\alpha \approx 2.4$. For the bilayer system we find a giant magnetic enhancement (GME) that oscillates strongly due to interference effects. This results in a strongly modified magnetic interlayer coupling, both in phase and magnitude, which may not be described in the pure Ruderman-Kittel-Kasuya-Yoshida (RKKY) picture. No anti-ferromagnetic coupling was found and by comparison with magnetically constrained calculations we show that the overall ferromagnetic coupling can be understood from the strong polarization of the Pd spacer.