Magnetostriction of RCo3 Compounds (R=Pr, Nd, Gd, Tb, Dy)

The magnetostriation of polycrystalline RCo
₃
compounds (R=Pr, Nd, Gd, Tb, Dy) in the temperature range from 77K to 350K was measured. The values of λ
_″
-λ
_⊥
at T=77K and H=20 kOe were -40×10
^-6
for R=Pr, -1080×10
^-6
for Nd, -80×10
^-6
for Gd, 2680×10
^-6
for Tb and -780×10
^-6
for Dy. The sign of λ
_″
-λ
_⊥
for DyCo
₃
at H=20 kOe changes from negative to positive at about 170K with increasing temperature. The dependence of the magnetostriction on the elements R in RCo
₃
compounds is discussed on the basis of the point-charge model.