Magnetic and Kondo Behavior of CeCoGe$_{2}$

There is great interest in exotic states among Ce-Kondo lattices. Recently, specific heat and magnetic susceptibility of CeCoGe$_2$ have been accounted by the S=5/2 Kondo model; i.e., no crystalline electric field (CEF) effects have been observed.$^1$ This result is surprising since related $^2$ CeNiGe$_2$, belonging to this crystal structure, exhibits strong anisotropy in magnetic and transport properties due to CEF’s. Our magnetic susceptibility and specific heat results on (Ce,La)CoGe$_2$ suggest that exotic properties of this system are due to magnetic interactions in a quasi-two-dimensional Ce-lattice. This work was supported by NSF, grant DMR-0104240. \\ \\ $^1$ E. D. Mun et al., Phys. Rev. B {\bf 69}, 85113 (2004).\\ $^2$ Y. Okada et al., J. Phys. Soc. Jpn. {\bf 72}, 2692 (2003).