Coercivity enhancement induced by substitutional Ni-dopin in van der Waals Ferromagnet Fe₃GaTe₂

Magnetic properties of well - defined crystals can be effectively tuned via substitutional doping of their magnetic core with other magnetic elements. In magnetic van der Waals (vdW) metal group Fe_XGeTe₂ (X=3, 5), substitutional doping of Fe to other transition metal elements such as Ni, Co induces the transition of crystal’s magnetic properties, which offers wider range of material pool for exploring physical phenomena in vdW magnet as well as applications. Although doped Fe_XGeTe₂ has been intensively researched for recent few years, doping effect of recently reported vdW ferromagnet Fe₃GaTe₂ hasn’t been reported yet. Here, we present the coercivity enhancement induced by substitutional Ni doping in Fe₃GaTe₂. Doping-induced coercivity enhancement is also reported in Co-doped Fe₃GeTe₂, which replaced ~58% of Fe with Co. This replacement decreases the curie temperature, from 220K to ~50K, which seems not adequate for applications. In our results, only small amount of Ni doping leads to dramatic increase of the coercivity of bulk crystal from 0.02T for un-doped one to ~0.7T. We speculate that the enhancement mainly originates from domain-wall pinning at Ni site, and further study is needed to clarify effects from other factors that are correlated to magnetic characteristic in metallic system, such as structural deformation, electrical doping, magnetic anisotropy energy, and etc.

Acknowledgements: This work was supported by Samsung Research Funding Center of Samsung Electronics (SRFC-MA2102-02)