Non-Fermi liquid behavior in Ce(Cu1-xNix)(2)Ge-2 and CeCu2(Si1-yGey)(2)

The heavy-fermion compounds Ce(Cu1-xNix)(2)Ge-2 and CeCu2(Si1-yGey)(2) were explored using electrical transport, magnetic susceptibility, and neutron scattering measurements. The hybridization of CeCu2Ge2 can be changed by substituting either Cu by Ni or Ge by Si. From the local type of antiferromagnetism in CeCu2Ge2 to the heavy-fermion superconductor CeCu2Si2, the systems reveal a rich magnetic phase diagram with up to three distinct phase transitions below 5 K. In the case of substituting Cu by Ni, the system shows a transition from a local-type of ordering to a band-like magnetism of heavy-fermions. For the concentration x approximate to 0.8 the magnetic order is suppressed and systematic deviations from the Fermi-liquid behavior are observed in the temperature dependence of the resistivity.