Perpendicular magnetic anisotropy at Fe/Au(111) interface studied by M\"{o}ssbauer, x-ray absorption, and photoemission spectroscopies

TL;DR

This study investigates the origin of perpendicular magnetic anisotropy at the Fe/Au(111) interface, revealing that it results from orbital hybridization and spin-orbit coupling effects, with implications for designing magnetic interfaces.

Contribution

The paper provides a detailed spectroscopic analysis demonstrating the role of $p$-$d$ hybridization and spin-orbit coupling in inducing interfacial PMA in Fe/Au(111).

Findings

Interfacial PMA is linked to orbital hybridization between Fe 3d and Au 6p bands.

Spectroscopy confirms the modulation of Fe's electronic structure due to proximity effects.

Spin-orbit coupling in Au plays a crucial role in the emergence of PMA.

Abstract

The origin of the interfacial perpendicular magnetic anisotropy (PMA) induced in the ultrathin Fe layer on the Au(111) surface was examined using synchrotron-radiation-based M\"{o}ssbauer spectroscopy (MS), X-ray magnetic circular dichroism (XMCD), and angle-resolved photoemission spectroscopy (ARPES). To probe the detailed interfacial electronic structure of orbital hybridization between the Fe 3$d$ and Au 6$p$ bands, we detected the interfacial proximity effect, which modulates the valence-band electronic structure of Fe, resulting in PMA. MS and XMCD measurements were used to detect the interfacial magnetic structure and anisotropy in orbital magnetic moments, respectively. $In$-$situ$ ARPES also confirms the initial growth of Fe on large spin-orbit coupled surface Shockley states under Au(111) modulated electronic states in the vicinity of the Fermi level. This suggests that PMA in the Fe/Au(111) interface originates from the cooperation effects among the spin, orbital magnetic moments in Fe, and large spin-orbit coupling in Au. These findings pave the way to develop interfacial PMA using $p$-$d$ hybridization with a large spin-orbit interaction.