Magnetostriction of (Fe-Co)3 Tb Compounds and Amorphous Fe3 Tb Alloys

The magnetostriction of (Fe
_1-x
Co
_x
) Tb (0≤×≤1.0) compounds and amorphous Fe
₃
Tb alloys were measured at room temperature and at 77K. The value of λ
_″
-λ
_⊥
at 77K and 20 kOe of (Fe
_1-x
Co
_x
)
₃
Tb compounds increases drastically from 1500×10
^-6
to 3000×10
^-6
as x is increased from 0 to 1.0. The value of λ
_″
-λ
_⊥
for amorphous Fe
₃
Tb is about 30 to 40% smaller than the value for the crystalline material. The effect of Co substitution on the magnetostriction of (Fe
_1-x
Co
_x
)Tb compounds is discussed on the basis of the single ion model. The magnetic field dependence of magnetostriction in Fe
₃
Tb amorphous alloy is also discussed in connection with the magnetization process.