Signature of canted ferromagnetism in van der Waals Fe5−<i>x</i>GeTe2 flakes

Abstract

Van der Waals ferromagnetic materials, serving as an innovative platform for tailoring magnetic anisotropy and anisotropic magnetoresistance, offer great opportunities for designing and manipulating spintronic devices. In this study, we report the observation of temperature-dependent magnetic anisotropy and anisotropic magnetoresistance in high-quality single crystals of the van der Waals ferromagnet Fe5−xGeTe2. Due to the rhombohedral structure of Fe5GeTe2, the Fe atoms occupy three different sites, resulting in complex magnetic properties. As the electronic structure changes with decreasing temperature in Fe5−xGeTe2, the magnetic anisotropy is affected and results in a spin-flop transition from an out-of-plane orientation to a canted orientation. At low temperatures, the angle-dependent magnetoresistance shows a dramatic change, indicating anisotropic magnetoresistance in different crystallographic axis. The presence of room-temperature magnetism and giant anisotropic magnetoresistance suggests promising potential for Fe5−xGeTe2 in spintronic applications.