Abstract
We investigated the Ru and O electronic structure and magnetic properties of an ultrahigh-quality film on grown by machine-learning assisted molecular-beam epitaxy. The high itinerancy and long quantum lifetimes of the quasiparticles in the Ru -O hybridized valence band are confirmed by observing the prominent well-screened peak in the Ru core-level photoemission spectrum, the coherent peak near the Fermi energy in the valence-band spectrum, and quantum oscillations in the resistivity. The element-specific magnetic properties and the hybridization between the Ru and O orbitals were characterized by Ru -edge and O -edge soft x-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements. The ultrahigh-quality film with the residual resistivity ratio of 86 shows the large orbital magnetic moment of oxygen ions induced by the strong orbital hybridization of the O states with the spin-polarized Ru states. The film also shows single-domain perpendicular magnetization with an almost ideal remanent magnetization ratio of 0.97. These results provide detailed insights into the relevance between orbital hybridization and the perpendicular magnetic anisotropy in systems.
1 More- Received 10 August 2021
- Accepted 10 November 2021
DOI:https://doi.org/10.1103/PhysRevMaterials.5.124403
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