Structure and magnetostriction of R(Fe1−xGax)1.85 and R(Fe1−xCrx)1.85 alloys (R=Dy0.65Tb0.25Pr0.1)

The structure, Curie temperature and magnetostriction of R(Fe1−xGax)1.85 and R(Fe1−xCrx)1.85 multicomponent pseudobinary alloys (R=Dy0.65Tb0.25Pr0.1, 0≤x≤0.2) have been investigated using optical microscopy, ac susceptibility, X-ray diffraction, and standard strain gauge techniques. It was found that the matrix of these alloys possesses cubic Laves' structure. The addition of gallium or chromium shifts the homogeneity range of the 1:2 compound towards the stoichiometric composition. The lattice parameter increases linearly, while the Curie temperature and the room temperature magnetostriction λ decrease rapidly with increasing Ga content. The solubility limit of Cr in (Dy, Tb, Pr)Fe2 compound is about x = 0.08. When x ≤ 0.08 the lattice parameter increases slowly, whereas the Curie temperature and the room temperature magnetostriction λ decrease gradually with increasing Cr content in high magnetic fields, but remain constant with further increase in Cr concentration. The magnetostriction in low magnetic fields (H≤4 kOe) for the R(Fe1−xCrx)1.85 alloy with x=0.02 is superior to that of the other alloys in this system.