Physical Vapor Transport Growth of Antiferromagnetic CrCl₃ Flakes Down to Monolayer Thickness

The van der Waals magnets CrX₃ (X = I, Br, and Cl) exhibit highly tunable magnetic properties and are promising candidates for developing novel two-dimensional (2D) spintronic devices such as magnetic tunnel junctions and spin tunneling transistors. Previous studies of the antiferromagnetic CrCl₃ have mainly focused on mechanically exfoliated samples. Controlled synthesis of high quality atomically thin flakes is critical for their technological implementation but has not been achieved to date. This work reports the growth of large CrCl₃ flakes down to monolayer thickness via the physical vapor transport technique. Both isolated flakes with well-defined facets and long stripe samples with the trilayer portion exceeding 60 µm have been obtained. High-resolution transmission electron microscopy studies show that the CrCl₃ flakes are single crystalline in the monoclinic structure, consistent with the Raman results. The room temperature stability of the CrCl₃ flakes decreases with decreasing thickness. The tunneling magnetoresistance of graphite/CrCl₃ /graphite tunnel junctions confirms that few-layer CrCl₃ possesses in-plane magnetic anisotropy and Néel temperature of 17 K. This study paves the path for developing CrCl₃ -based scalable 2D spintronic applications.