Low-temperature properties of an Yb impurity in a metallic host with an axial crystalline field

Abstract

The Bethe-Ansatz equations for the ground state of the Coqblin-Schrieffer model for j=(7/2 are solved for a special axial-crystal-field-splitting scheme. The occupations of the crystal-field levels, the specific-heat contribution linear in the temperature, and the magnetic susceptibility parallel and perpendicular to the crystal axis are obtained as a function of the crystal-field strength. The universality of the results is discussed and a comparison with experiments on ${\mathrm{YbCu}}_2$ ${\mathrm{Si}}_2$ and YbCuAl is made.