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

The magnetostriation of polycrystalline RCo3 compounds (R=Pr, Nd, Gd, Tb, Dy) in the temperature range from 77K to 350K was measured. The values of ¿¿-¿¿ 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 ¿¿-¿¿ for DyCo3 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 RCo3 compounds is discussed on the basis of the point-charge model.