Voltage control of magnetism through electric field-induced oxygen motion (magneto-ionics) could represent a significant breakthrough in the pursuit for new strategies to enhance energy efficiency in a large variety of magnetic devices, such as magnetic micro-electro-mechanical systems (MEMS), magnetic logics, spin electronics, or neuromorphic computing, i.e., envisaging ultra-low power emulation of the biological synapse. Boosting the induced changes in magnetization, magneto-ionic motion and cyclability (endurance) continue to be key challenges to turn magneto-ionic phenomena into real applications. Here, we demonstrate that, without degrading cyclability, room temperature magneto-ionic motion in electrolyte-gated paramagnetic and fairly thick (> 100 nm) Co3O4 films largely depends on the configuration used to apply the electric field. In particular, magneto-ionic effects are significantly increased both in terms of generated magnetization (6 times larger: from 118.5 to 699.2 emu cm-3) and speed (35 times faster: from 33.1 to 1170.8 emu cm-3 h-1) if the electric field is applied across a conducting buffer layer (grown underneath the Co3O4 films), instead of directly contacting Co3O4. This is attributed to a greater uniformity and strength of the applied electric field when using the conducting layer. These results may trigger the use of oxygen magneto-ionics into promising new technologies, such as magnetic MEMS or brain-inspired computing, which require endurance and moderate speeds of operation.
@article{arxiv.2001.08181,
title = {Boosting room temperature magneto-ionics in Co3O4},
author = {Julius de Rojas and Alberto Quintana and Aitor Lopeandía and Joaquín Salguero and José L. Costa-Krämer and Llibertat Abad and Maciej O. Liedke and Maik Butterling and Andreas Wagner and Lowie Henderick and Jolien Dendooven and Christophe Detavernier and Jordi Sort and Enric Menéndez},
journal= {arXiv preprint arXiv:2001.08181},
year = {2020}
}