Persistent ferromagnetic ground state in pristine and Ni-doped Fe3GaTe2 flakes

Room-temperature magnetism and its stability upon miniaturization are essential characteristics required for materials for spintronic devices and information storage. Among various candidates, Fe₃GaTe₂ stands out due to its high Curie temperature and strong perpendicular magnetic anisotropy (PMA), recently gaining large attention as one of the promising candidate materials for spintronics applications. In this study, we measured the thickness-dependent ferromagnetic properties of Fe₃GaTe₂ and (Fe_1 − xNi_x)₃GaTe₂ (with x = 0.1) flakes. We observed that both pristine and Ni-doped Fe₃GaTe₂ exhibit persistent ferromagnetism, with only a minor decrease in T_C as the thickness is reduced to a few tens of nanometers. This capacity to retain robust ferromagnetic properties at reduced dimensions is highly advantageous for thin-film applications, which is crucial for the scaling of spintronic devices. Understanding and controlling thickness-dependent magnetic properties is fundamental to harnessing the full potential of Fe₃GaTe₂ in van der Waals magnetic heterostructures and advanced spintronic technologies.