Magnetostriction in dilute silver—rare-earth monocrystals

From magnetostriction measurements on silver monocrystals doped with rare earths at about 0.5 at.% concentration, we estimate the ion-lattice coupling parameters. For each monocrystal the $〈001〉$ and $〈111〉$ shape magnetostrictions have the same sign and follow the sign of the quadrupolar Stevens factor $\alpha$ of the rare-earth impurity. Higher-order terms cannot be neglected. The volume magnetostriction for $〈001〉$ fields is an order of magnitude smaller than the shape effect and is positive for each sample.