Materials that combine a structure of layers with thicknesses of only few atoms with magnetic properties are promising for future technological applications either by themselves or together with other layered materials in so-called heterostructures. For such applications, it is important to be able to deliberately influence and tune the magnetic properties. One way to achieve this is by substitution, i.e., by replacing one (magnetic) element by another.
A research group of the IFW Dresden has recently studied the effects of replacing iron (Fe) with nickel (Ni) in the layered material (Fe1-xNix)2P2S6 on its magnetic properties. For this purpose, several materials with different iron/nickel ratios were prepared as single crystals. Only in single crystals, due to the well-defined structure of the sample, it is possible to determine the directional dependence of magnetism. Surprisingly, we find that even materials with high nickel contents (e.g., (Fe0.1Ni0.9)2P2S6) still exhibit very similar dependence as the material without any Ni, i.e., pure Fe2P2S6. In contrast, Ni2P2S6 exhibits a directional dependence of magnetism that is significantly different from all other materials studied.
Please find more details about the topic in the original publication: S. Selter, Y. Shemerliuk, M.-I. Sturza, A. U. B. Wolter, B. Büchner, and S. Aswartham, Crystal growth and anisotropic magnetic properties of quasi-two-dimensional (Fe1−xNix)2P2S6, Phys. Rev. Materials 5, 073401 (2021).