Evolution of itinerant electron magnetism in the (Sc, Nb)Fe2 system in spin-fluctuation theory
The magnetic behavior of the (Sc, Nb)Fe2 series of intermetallic compounds was thoroughly investigated in the ordered ferromagnetic state as well as in the paramagnetic regime.system. The experimental results were analyzed in the frame of Kuz’min’s model describing the temperature dependence of the spontaneous magnetization, and Takahashi’s theory of spin fluctuations. The longitudinal spin fluctuations progressively increase for the richest Nb compositions, by contrast, transverse spin fluctuations dominate for the parent compound ScFe2. Furthermore, a reduction in ferromagnetic
interactions upon Nb for Sc substitution is observed, resulting in an evolution from a short-range ferromagnet for ScFe2 to systems with competing exchange
interactions for Nb-rich composition. Nb-rich (Sc, Nb)Fe2 compounds evolve progressively toward the weakly ferromagnetic limit. Spin-fluctuation parameters have been determined from magnetic measurements using Takahashi’s model. We report an evolution from mostly localized magnetic character of Fe moments to a strongly delocalized one upon increasing the Nb content along the Sc1−xNbxFe2 series of compounds.
