The electric field gradient of the transition element impurity 99Ru in metallic hosts of Gd, Tb, Dy, Ho, and Lu

The electric fieldgradient of the transition element impurity 99Ru in metallic hosts of the rare earth series Gd, Tb, Dy, Ho, Er, and Lu has been investigated as a function of temperature by time differential perturbed angular correlation measurements. In all rare earth metals the fieldgradient of 99Ru is more than a factor of 10 Larger than the ionic contribution (1-γsub(infinite)) Vsub(z)sub(z)sub(,)sub(l)sub(a)sub(t). Therefore these systems are not compatible with the concept of an universal correlation between ionic and electronic fieldgradient. The temperature dependence of the electric fieldgradient is extremely weak. In most cases it changes less than 3% between 200 K and 800 K. These results suggest a strong contribution to the fieldgradient from the unclosed 4d-shell of the impurity. (orig.)