Effect of Co or Ni substitution on magnetism in the layered van der Waals ferromagnet Fe3GaTe2

We have grown a series of single crystals of two-dimensional van der Waals ferromagnet $\mathrm{F}{\mathrm{e}}_{3}\mathrm{GaT}{\mathrm{e}}_{2}$ substituted with Co or Ni. The large single crystals of ${(\mathrm{F}{\mathrm{e}}_{1\ensuremath{-}x}\mathrm{C}{\mathrm{o}}_{x})}_{3}\mathrm{GaT}{\mathrm{e}}_{2} (0\ensuremath{\le}x\ensuremath{\le}0.55)$ and ${(\mathrm{F}{\mathrm{e}}_{1\ensuremath{-}x}\mathrm{N}{\mathrm{i}}_{x})}_{3}\mathrm{GaT}{\mathrm{e}}_{2} (0\ensuremath{\le}x\ensuremath{\le}0.46)$ were characterized with x-ray diffraction, magnetic susceptibility, electrical resistivity, and Hall measurements. Our results show that the magnetic transition temperatures of $\mathrm{F}{\mathrm{e}}_{3}\mathrm{GaT}{\mathrm{e}}_{2}$ are gradually suppressed upon Co or Ni doping. A small amount of Co or Ni doping results in a significant increase of the coercive field. In particular, Co doping tunes the crystals from ferromagnetism to antiferromagnetism and then to the spin-glass state, while Ni doping tunes the crystals from ferromagnetism to spin-glass states. The strong doping-dependent magnetic properties suggest that $\mathrm{F}{\mathrm{e}}_{3}\mathrm{GaT}{\mathrm{e}}_{2}$ has great potential for spintronic applications.