Hydrogen-induced reversible spin-reorientation transition and magnetic stripe domain phase in bilayer Co on Ru(0001)

TL;DR

This study demonstrates a reversible hydrogen-induced spin-reorientation transition in a cobalt bilayer on Ru(0001), revealing how hydrogen adsorption and desorption modulate magnetic domain structures and anisotropy.

Contribution

It provides real-time imaging and ab-initio insights into hydrogen's role in controlling magnetic phase transitions in ultrathin cobalt films.

Findings

Hydrogen sorption reduces out-of-plane magnetic domains

Formation of magnetic stripe domain pattern due to decreased anisotropy

Reversible transition to in-plane magnetization upon hydrogen desorption

Abstract

Imaging the change in the magnetization vector in real time by spin-polarized low-energy electron microscopy, we observed a hydrogen-induced, reversible spin-reorientation transition in a cobalt bilayer on Ru(0001). Initially, hydrogen sorption reduces the size of out-of-plane magnetic domains and leads to the formation of a magnetic stripe domain pattern, which can be understood as a consequence of reducing the out-of-plane magnetic anisotropy. Further hydrogen sorption induces a transition to an in-plane easy-axis. Desorbing the hydrogen by heating the film to 400 K recovers the original out-of-plane magnetization. By means of ab-initio calculations we determine that the origin of the transition is the local effect of the hybridization of the hydrogen orbital and the orbitals of the Co atoms bonded to the absorbed hydrogen.