Néel vector driven spin current in a van der Waals antiferromagnetic insulator ( CrCl3 )/heavy metal (Pt) bilayer

Abstract

The widely distributed GHz to THz spin dynamics of antiferromagnets, combined with the recent demonstration of spin pumping, underscores the potential of dynamic antiferromagnetic devices. Here, we report antiferromagnetic spin pumping from a van der Waals antiferromagnetic insulator ${\text{CrCl}}_{3}$. Spin pumping driven by the N\'eel vector and the net magnetization has been verified, by adjusting the angle between two sublattice magnetizations from ${180}^{\ensuremath{\circ}}$ to ${0}^{\ensuremath{\circ}}$ while measuring the spin pumping voltages. An enhancement of acoustic mode spin current while decreasing the angle is observed, which proves the spin current is driven by the net magnetization. However, the optical mode spin current increases first and then decreases with the decreasing angle, which proves the optical mode spin current is driven by the N\'eel vector. These findings reveal the underlying contributions of $\mathbit{n}$ in antiferromagnets, and its distinctive role in antiferromagnetic spin pumping.