Magnetic structure in the two-dimensional van der Waals ferromagnet Fe${}_3$GaTe${}_2$

Abstract

High-quality single crystals of the two-dimensional van der Waals ferromagnet Fe${}_3$GaTe${}_2$ (FGaT) were successfully grown using the chemical vapour transport method, which effectively reduced surface impurities compared with conventional self-flux growth. Structural and magnetic characterizations were performed using single-crystal X-ray and neutron diffraction. The results confirm that FGaT crystallizes in the hexagonal $P{6}_3/mmc$ structure, with Fe occupying two inequivalent sites (Fe${}^i$ and Fe${}^{ii}$), where the magnetic moment of Fe${}^i$ [1.9(2) $\hat{I}{¼}_B$] is larger than that of Fe${}^{ii}$ [1.4(6) $\hat{I}{¼}_B$]. The magnetic easy axis is oriented along the $c$ axis and the Curie temperature ($T_C$) is approximately 355-360 K. Compared with Fe${}_3$GeTe${}_2$ (FGT), FGaT exhibits a slightly expanded $a$ axis and a contracted $c$ axis, resulting in a reduction in the Fe${}^i$-Fe${}^{ii}$ interatomic distance along the $c$ axis. This pronounced contraction could strengthen the Fe$-$Fe exchange interaction, which is believed to be the key factor responsible for the significantly higher $T_C$ in FGaT relative to FGT.

J. Appl. Cryst. (2026)