Magnetic and magnetostrictive properties have been investigated for amorphous (Tb0.27Dy0.73)
(Fe1-xCox)2 thin films. An increase in the 3d magnetic moment due to the enhancement of T-T interactions
in substituted (Fe, Co) alloys was found. This leads to stronger R-(Fe, Co) exchange energies and then to
enhancements of R-sublattice magnetization as well as magnetostriction in these amorphous R(Fe, Co) thin
films. In addition, a well-defined in-plane anisotropy is created by magnetic-field annealing for the Co-rich
films. A large magnetostriction of 480??10-6 developed in low fields of 0.3 T was observed for films with x
= 0.47 after magnetic-field annealing. The differing roles of Fe and Co atoms on the magnetization process
have also been discussed. ?? 2000 American Institute of Physics.
