La-alloying study ofCeCoGe2: Magnetic susceptibility and specific heat measurements

Abstract

We report measurements of magnetic susceptibility and specific heat for polycrystalline ${\mathrm{Ce}}_{1\ensuremath{-}x}{\mathrm{La}}_{x}\mathrm{Co}{\mathrm{Ge}}_{2}$ for $x=0$, 0.1, 0.2, 0.3, 0.5, and 1. $\mathrm{Ce}\mathrm{Co}{\mathrm{Ge}}_{2}$ is considered as a concentrated $J=5∕2$ Kondo system. We have found significant preferential orientation in the magnetic susceptibility implying magnetic anisotropy. Magnetic susceptibility and specific heat results do not corroborate the single impurity model and imply the importance of crystalline electric fields and magnetic correlations. Low-temperature specific heat and susceptibility data for $x=0.2$ suggest a possibility of a two-dimensional antiferromagnetic quantum critical point.