Co doping effect on the spin dynamics of high Tc Fe5GeTe2 vdW ferromagnet

Fe5GeTe2 (F5GT) is among the few van der Waals (vdW) ferromagnets (FMs) having near-room temperature magnetic transition. Substitutional Co further increases the macroscopic magnetic transition temperature (Tc) while reducing the Fe magnetic moment. These concomitant effects suggest an interplay between delocalized electrons and local moments that cannot be expressed in the frame of a purely itinerant electrons model. In this respect, Co-doped F5GT appears as an interesting platform where to explore spin dynamics in high Tc FMs. In this experiment, we propose to measure by RIXS the magnetic excitations in epitaxial F5GT and study the effects of Co doping on the spin wave dispersion.