Magnetic order in the van der Waals magnet VCl3

Abstract

We investigated the structural and magnetic properties of single-crystalline VCl3, a newly synthesized member of the vanadium trihalide family. High-quality single crystals were grown by the chemical vapor transport method, and their behavior was characterized using neutron diffraction and thermodynamic measurements. We show that VCl3 crystallizes in the BiI3-type structure at room temperature and undergoes a structural phase transition at 𝑇𝑆=103.7⁢(5)⁢K that lowers the lattice symmetry, followed by a zigzag antiferromagnetic order with a propagation vector 𝑘=(0,0.5,1) below 𝑇𝑁=21.8⁢(1)⁢K. Neutron diffraction experiments indicate that the ordered moments are canted by approximately 21∘ away from the 𝑐 axis toward the 𝑎 axis, yielding a total moment of approximately 1.09⁢(2)⁢𝜇B/V3+. Field-dependent magnetization along the 𝑐 axis exhibits a half magnetization plateau, indicative of a field-stabilized fractional state. These results establish VCl3 as a new platform for exploring structural transitions, anisotropic magnetism, and field-induced phases in vanadium-based honeycomb magnets.