Perpendicular magnetic anisotropy (PMA) and Dzyaloshinskii-Moriya interactions are key interactions in modern spintronics. These interactions are thought to be dominated by the oxidation of the Co|Al interface in the archetypal Platinum-Cobalt-Aluminum oxide system. Here, we observe a double sign change in the anisotropy and about threefold variation in interfacial chiral interaction, influenced not only by the oxidation, but also by the metallic Al thickness. Contrary to previous assumptions about negligible spin-orbit effects at light metal interfaces, we not only observe strong PMA with fully oxidized Al, decreasing and turning negative (in-plane) with less oxygen at the Co|Al interface, we also observe that the magnetic anisotropy reverts to positive (out-of-plane) values at fully metallic Co|Al interface. These findings suggest modification in Co d band via Co|Al orbital hybridization, an effect supported by X-ray absorption spectroscopy and ab initio theory calculations, highlighting the key impact of strain on interfacial mechanisms at fully metallic Co|Al interface.
@article{arxiv.2409.10685,
title = {Interfacial spin-orbitronic effects controlled with different oxidation levels at the Co|Al interface},
author = {Sachin Krishnia and Libor Vojáček and Tristan Da Câmara Santa Clara Gomes and Nicolas Sebe and Fatima Ibrahim and Jing Li and Luis Moreno Vicente-Arche and Sophie Collin and Thibaud Denneulin and Rafal E. Dunin-Borkowski and Philippe Ohresser and Nicolas Jaouen and André Thiaville and Albert Fert and Henri Jaffrès and Mairbek Chshiev and Nicolas Reyren and Vincent Cros},
journal= {arXiv preprint arXiv:2409.10685},
year = {2024}
}