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

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism

Background:

• Strong magnetic frustration suppresses magnetic order, but weak frustration can lead to complex magnetic structures like cycloids or spin density waves.
• Two-dimensional (2D) van der Waals materials offer unique platforms for exploring fundamental physics and novel applications.

Purpose of the Study:

• To investigate the magnetic properties of the weakly magnetically frustrated 2D van der Waals material CrPSe3.
• To characterize the magnetic order and crystal structure of CrPSe3.
• To explore the potential of CrPSe3 for spintronics and quantum devices.

Main Methods:

• Synthesis of polycrystalline CrPSe3 at an optimized temperature (700 °C) to ensure phase purity.
• Magnetic susceptibility measurements to determine the antiferromagnetic transition temperature (TN) and Curie-Weiss temperature (θCW).
• Neutron diffraction measurements to reveal the nature of the long-range magnetic order.
• Raman spectroscopy to confirm the preservation of the monoclinic crystal structure (C2/m symmetry).

Main Results:

• CrPSe3 exhibits an antiferromagnetic transition at TN ≈ 127 K with a large negative Curie-Weiss temperature (θCW ≈ -301 K), indicating weak magnetic frustration (f ≈ 2.4).
• Neutron diffraction confirmed the formation of a long-range incommensurate antiferromagnetic order below 120 K.
• The monoclinic crystal structure (C2/m) remained stable down to 20 K.

Conclusions:

• CrPSe3 is a novel 2D van der Waals material displaying incommensurate antiferromagnetic order, a phenomenon not previously observed in the MPX3 family.
• These findings enrich the understanding of magnetism in 2D materials and suggest potential applications in spintronics and quantum devices.