Possible origin of the resistivity maximum in heavy-fermion systems

The temperature $T_M$ of the resistivity maximum in ${\mathrm{CeCu}}_2$ ${\mathrm{Si}}_2$ and other heavy-fermion compounds has been assumed by some authors to be directly related to the value of the Kondo temperature $T_K$ in the same compound. In the present paper, I present evidence that, as is well known for spin-glasses, the Ruderman-Kittel-Kasuya-Yosida interaction between magnetic ions in heavy-fermion systems plays an important or even dominant role in determining the value of $T_M$. It is argued that across the quasiternary series ${\mathrm{La}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Ce}}_{\mathrm{x}}$ ${\mathrm{Cu}}_2$ ${\mathrm{Si}}_2$ the increase of $T_K$ with x is small, only doubling in value across the series.