Efficient non-collinear antiferromagnetic state switching induced by orbital Hall effect in chromium

TL;DR

This paper demonstrates efficient switching of antiferromagnetic states in Mn3Sn/Cr heterostructures induced by orbital Hall effect, highlighting Cr's potential as a spin current source despite its small spin Hall angle.

Contribution

It reveals that Cr can effectively generate orbital currents leading to antiferromagnetic switching, expanding the scope of materials for spintronics beyond heavy metals.

Findings

Cr-based heterostructures exhibit comparable switching current densities to heavy metals.

Orbital current generation in Cr is confirmed by terahertz emission and magnetoresistance measurements.

Cr's diffusion length (~11 nm) indicates efficient orbital-to-spin current conversion.

Abstract

Recently orbital Hall current has attracted attention as an alternative method to switch the magnetization of ferromagnets. Here we present our findings on electrical switching of antiferromagnetic state in Mn3Sn/Cr, where despite the much smaller spin Hall angle of Cr, the switching current density is comparable to heavy metal based heterostructures. On the other hand, the inverse process, i.e., spin-to-charge conversion in Cr-based heterostructures is much less efficient than the Pt-based equivalents, as manifested in the almost one order of magnitude smaller terahertz emission intensity and spin current induced magnetoresistance in Cr-based structures. These results in combination with the slow decay of terahertz emission against Cr thickness (diffusion length of ~11 nm) suggest that the observed magnetic switching can be attributed to orbital current generation in Cr, followed by efficient conversion to spin current. Our work demonstrates the potential of light metals like Cr as an efficient orbital/spin current source for antiferromagnetic spintronics.