A structural study and some magnetic properties of the (Sc,Nb)Fe2 series of compounds

We report on the effects of Nb for Sc substitution on the structural and magnetic properties of the Sc1-xNbxFe2 series of compounds by means of scanning electron microscopy, energy dispersive X-ray microanalysis, X-ray powder diffraction, and magnetic measurements. The study focus on hexagonal P63/mmc crystal symmetry structure of the ScFe2 phase retained along the series. Whereas the unit cell is found to decrease regularly upon increasing the niobium content the magnetic properties are found to evolve in a non monotonous manner. A drop of the magnetization and Curie temperature is observed upon substitution, the highest TC being 530 K. Indeed, it is shown that Nb for Sc substitution induces dramatic changes of the magnetic properties such as a strong decrease of the ordering temperature and significant reduction of the spontaneous magnetization for Nb content above x=0.2 and 0.1, respectively. The highest magnetization is found for the Sc rich side with values of about 2.6 µB/f.u. corresponding to 1.3 µB/Fe atom. Moreover, compounds with x=0.75 and 1 are no longer exhibiting ferromagnetic order even at 2 K. The easy magnetization direction of Sc1-xNbxFe2 series of compounds is determined to be along the c-axis at room temperature. •Hexagonal P63/mmc crystal symmetry retained along the series.•Composition dependence of the unit-cell parameters.•Overall volume contraction of ΔV/V = 8.6%.•Evolution of TC and MS upon Nb for Sc substitution.•Easy magnetization direction of ScFe2 is along c-axis.