Magneto-elastic behaviour of a terbium single crystal

The ordinary anisotropic magnetostriction of rather small terbium single crystals in the ferro, antiferro and paramagnetic regions is reported. The small specimen thickness necessitated corrections to be made which amounted to an increase in the observed magnetostriction data of 14 %. The evaluation of this correction is discussed. The basal-plane magnetostriction coefficients obey the single-ion Îl + 1/2 law (Callen and Callen 1965) over ferro and paramagnetic regions with normalization values of Other coefficients could not be measured in the ferromagnetic region because a large anisotropy confines magnetic moments to the basal plane. The coefficients λε2 and λ2 α,2 have been obtained in the paramagnetic region. Assuming the single-ion magnetization dependence, an extrapolation to 0°K yields the values: λε,2(0) = 20×10−3 and λ2 α,2(0) = 15 × 10−3.