Anisotropy compensation and magnetostrictive properties in Tbx Dy1−x(Fe0.9Mn0.1)1.93 Laves compounds: Experimental and theoretical analysis

The structure, magnetic transitions, and magnetostriction of Tbx Dy1−x(Fe0.9Mn0.1)1.93 polycrystalline compounds have been investigated. The Mn substitution for Fe changes the composition for the anisotropy compensation to the Dy-rich side compared with the Tbx Dy1−xFe2 system, which was confirmed by the analysis of detailed scanned XRD, the temperature dependence of a.c. initial susceptibility χac(T), and the calculation of the first anisotropy constant K1. The spin configuration diagram accompanied with different crystal structures for TbxDy1−x(Fe0.9Mn0.1)1.93 was constructed. The large tetragonal distortion λ100 due to the Mn substitution for Fe could be ascribed to the change in d band structure. The largest ratio between magnetostriction and the absolute values of the first anisotropy constant λa/|K1| appears at the composition with x=0.26, which could make it potential material for magnetostrictive application. Based on our experimental results, a phenomenological approach was also proposed to theoretically demonstrate that the facilitated magnetization rotation and enhanced magnetostriction are a consequence of the anisotropic flattening of Gibbs free energy.