Fluctuation-Mediated Spin-Orbit Torque Enhancement in the Noncollinear Antiferromagnet Mn<sub>3</sub>Ni<sub>0.35</sub>Cu<sub>0.65</sub>N.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40356435.
- Also identified by DOI 10.1021/acs.nanolett.4c05423 and PMC identifier 12100721.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
We report strong spin-orbit torques (SOTs) generated by noncollinear antiferromagnets Mn<sub>3</sub>Ni<sub>0.35</sub>Cu<sub>0.65</sub>N, over a wide temperature range. The SOT efficiency peaks up to 0.3 at the Néel temperature (<i>T</i><sub><i>N</i></sub>), substantially higher than that of commonly studied nonmagnets, such as Pt. The sign and magnitude of the SOTs measured in our experiments are corroborated by density functional theory, confirming the dominance of the orbital Hall effect over the spin Hall effect in the nonmagnetic phase above <i>T</i><sub><i>N</i></sub>. In contrast, the strong temperature-dependent SOTs observed around and below <i>T</i><sub><i>N</i></sub> can be explained by recently developed mechanisms involving chirality-induced and extrinsic scattering-driven spin and orbital currents, considering the effect of spin fluctuations at finite temperatures. Our work not only reports a large magnitude of SOT but also sheds light on a new possible origin where orbital currents can be harnessed by leveraging the chirality of noncollinear antiferromagnets, which holds promise for magnetic memory applications.