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 less than or equal to x less than or equal to 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 lambda(s) decrease rapidly with increasing Ga content. The solubility limit of Cr in (DY, Tb, Pr)Fe-2 compound is about x=0.08. When x less than or equal to 0.08 the lattice parameter increases slowly, whereas the Curie temperature and the room temperature magnetostriction lambda(s) 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 less than or equal to 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. (C) 1997 Elsevier Science S.A.