Complete mapping of magnetic anisotropy for prototype Ising van der Waals FePS$_3$

TL;DR

This study provides a comprehensive 3D mapping of magnetic anisotropy in FePS$_3$, combining experimental torque magnetometry with theoretical calculations, advancing understanding of magnetic behavior in van der Waals Ising materials.

Contribution

First complete 3D mapping of magnetic anisotropy in FePS$_3$ using combined experimental and theoretical methods.

Findings

Confirmed the easy axis is perpendicular to the ab plane.

Revealed anisotropies within the ab, ac, and bc planes.

Demonstrated the approach's applicability to other vdW magnetic materials.

Abstract

Several Ising-type magnetic van der Waals (vdW) materials exhibit stable magnetic ground states. Despite these clear experimental demonstrations, a complete theoretical and microscopic understanding of their magnetic anisotropy is still lacking. In particular, the validity limit of identifying their one-dimensional (1-D) Ising nature has remained uninvestigated in a quantitative way. Here we performed the complete mapping of magnetic anisotropy for a prototypical Ising vdW magnet FePS$_3$ for the first time. Combining torque magnetometry measurements with their magnetostatic model analysis and the relativistic density functional total energy calculations, we successfully constructed the three-dimensional (3-D) mappings of the magnetic anisotropy in terms of magnetic torque and energy. The results not only quantitatively confirm that the easy axis is perpendicular to the $ab$ plane, but also reveal the anisotropies within the $ab$, $ac$, and $bc$ planes. Our approach can be applied to the detailed quantitative study of magnetism in vdW materials.