Fe${}_{5\text{â}\text{ˆ}\text{’}x}$Ge${}_2$Te${}_2$. A new exfoliable itinerant ferromagnet with high Curie temperature and large perpendicular magnetic anisotropy

Layered van der Waals (vdW) crystals with intrinsic magnetic properties such as high Curie temperature (T${}_C$) and large perpendicular magnetic anisotropy (PMA) are key to the development and application of spintronic devices. The ferromagnetic vdW metal Fe${}_{3\text{â}\text{ˆ}\text{’}x}$GeTe${}_2$ (FGT) has gained prominence recently due to its high T${}_C$ (220 K) and strong PMA. Herein, a new metallic vdW ferromagnet, Fe${}_{5\text{â}\text{ˆ}\text{’}x}$Ge${}_2$Te${}_2$ or FG2T, is introduced, which is 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. Novel heterostructure devices with near‐room‐temperature capabilities using FG2T as a spin injector are enabled by this work. (© 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)