Magnetism and superconductivity in CeCu2Si2 single-crystals.

Single crystals of CeCu2Si2 were grown from metal solvents and their magnetic properties were systematically varied by partial substitution of Cu by Sn or In. The susceptibility chi is anisotropic and at high temperatures it is dominated by the crystal field split 4f state. At low temperatures the magnetic moments are drastically reduced. This reduction, as well as the Curie-Weiss temperature, depends sensitively upon the chemical composition.