Magnetostriction of Dy-rich TbxDy1-x single crystals

Magnetostriction and differential scanning calorimetry measurements were conducted on the Tb_xDy_1-x alloy system for 0.33⩾x⩾0. The magnetostriction measurements extend from 80 K to 300 K and cover the ferromagnetic, antiferromagnetic spiral, and paramagnetic temperature regions with fields of 6-20 kOe. From the data the authors derive the two lowest order magnetostriction constants, λ^γ.2 and λ^γ.4, as well as the basal plane anisotropy, K ₆⁶. At 80 K, λ^γ.2>7×10^-3 for all alloys. While λ^γ.2 is almost independent of alloy concentration (except at high temperatures), λ^γ.4 decreases substantially with increasing Dy concentration, approaching zero for 0.17>x>0. As reported previously, the basal plane anisotropy was found to compensate at temperatures below 100 K in the x=0.67 and 0.50 alloys. This compensation is found to occur at higher temperatures in the x=0.33 and 0.17 alloys. The temperatures at which this occurs are presented in a magnetic phase diagram along with the calorimetrically determined Curie and Neel temperatures