Magnetic behavior of Ce(${\mathrm{Cu}}_{1\mathrm{-}\mathrm{x}}$${\mathrm{Ag}}_{\mathrm{x}}$${)}_6$

We have investigated doped ${\mathrm{CeCu}}_6$ via x-ray diffraction, dc and ac susceptibility, and specific heat in zero and applied magnetic field with a primary focus on the magnetic behavior caused by Ag doping. We present evidence from bulk specific heat and metallography data that the limit of Ag solubility in Ce(${\mathrm{Cu}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Ag}}_{\mathrm{x}}$ ${)}_6$ is x∼0.1. Data below the magnetic ordering temperature may be fit to an exponential temperature dependence, implying a weak-coupled energy gap of Δ=0.58 K, contradicting an earlier report that C behaves linearly with temperature with a γ over 3 J/mol ${\mathrm{K}}^2$ in the ordered state. Comparisons to magnetically ordered, doped ${\mathrm{UPt}}_3$ are made.