Fe$_{5-x}$Ge$_2$Te$_2$ -- A new exfoliable itinerant ferromagnet with high Curie temperature and large perpendicular magnetic anisotropy

TL;DR

This paper reports the discovery and characterization of Fe$_{5-x}$Ge$_2$Te$_2$, a new exfoliable van der Waals ferromagnet with a high Curie temperature of 250 K and large perpendicular magnetic anisotropy, suitable for spintronic applications.

Contribution

Introduces a new metallic van der Waals ferromagnet, Fe$_{5-x}$Ge$_2$Te$_2$, with high Curie temperature and large magnetic anisotropy, expanding the family of 2D magnetic materials.

Findings

Fe$_{5-x}$Ge$_2$Te$_2$ orders ferromagnetically at 250 K

Exhibits large perpendicular magnetic anisotropy

Suitable for near room temperature spintronic devices

Abstract

Layered van der Waals (vdW) crystals with intrinsic magnetic properties such as high Curie temperature (TC) and large perpendicular magnetic anisotropy (PMA) are key to the development and application of spintronic devices. The ferromagnetic vdW metal Fe3-xGeTe2 (FGT) has gained prominence recently due to its high TC (220 K) and strong PMA. Here, we introduce a new metallic vdW ferromagnets, Fe5-xGe2Te2 or FG2T, which was successfully synthesized and fully characterized. FG2T is a metal that orders ferromagnetically with a very sharp transition at 250 K (bulk and single crystal thin flakes) and shows large PMA, as found by both experimental and computational studies. This work enables novel heterostructure devices with near room temperature capabilities by using FG2T as spin injector.