Incommensurate Antiferromagnetic Order in Weakly Frustrated Two-Dimensional van der Waals Insulator CrPSe3

The two-dimensional (2D) van der Waals(vdW) material MPX3 with a hexagonal-like arrangement oftransition metal atomsin the vdW layers has a diversity of commensurate antiferromagneticorders. Distinctly, CrPSe3 reveals a weakly frustratedincommensurate antiferromagnetic order without structural phase transition. Although magnetic order is suppressed by a strong frustration,it appears in complex forms such as a cycloid or spin density wavein weakly frustrated systems. Herein, we report a weakly magneticallyfrustrated two-dimensional (2D) van der Waals material CrPSe3. Polycrystalline CrPSe3 was synthesized at an optimizedtemperature of 700 & DEG;C to avoid the formation of any secondaryphases (e.g., Cr2Se3). The antiferromagnetictransition appeared at T (N) & AP; 127K with a large Curie-Weiss temperature & theta;(CW) & AP; -301 K via magnetic susceptibility measurements,indicating weak frustration in CrPSe3 with a frustrationfactor of f (|& theta;(CW)|/T (N)) & AP; 2.4. Evidently, the formation of a long-rangeincommensurate antiferromagnetic order was revealed by neutron diffractionmeasurements at low temperatures (below 120 K). The monoclinic crystalstructure of the C2/m symmetry ispreserved over the studied temperature range down to 20 K, as confirmedby Raman spectroscopy measurements. Our findings on the incommensurateantiferromagnetic order in 2D magnetic materials, not previously observedin the MPX3 family, are expected to enrich the physicsof magnetism at the 2D limit, thereby opening opportunities for theirpractical applications in spintronics and quantum devices.

Automated summary

This article reports a weakly magnetically frustrated two-dimensional (2D) van der Waals material CrPSe3, which exhibits an incommensurate antiferromagnetic order, as revealed by magnetic susceptibility and neutron diffraction measurements. This discovery enriches the physics of 2D magnetic materials and opens up opportunities for their practical applications in spintronics and quantum devices.