The results of magnetic susceptibility, electrical resistivity $\left(\rho \right)$, and heat-capacity measurements as a function of temperature are reported for the alloys, ${\mathrm{Ce}}_2{\mathrm{Rh}}_{1-x}{\mathrm{Co}}_x{\mathrm{Si}}_3$, crystallizing in an $\mathrm{Al}{\mathrm{B}}_2$-derived hexagonal structure. ${\mathrm{Ce}}_2\mathrm{Rh}{\mathrm{Si}}_3$ exhibits antiferromagnetic ordering at $7\mathrm{K}$. The Néel temperature decreases gradually with the increase in Co concentration. For $x⩾0.6$, no magnetic ordering is observed down to $0.5\mathrm{K}$. Interestingly, the $x=0.6$ alloy exhibits signatures of non-Fermi-liquid behavior, while the Co end member is a Fermi liquid. Thus, a transformation of magnetic-ordering state to nonmagnetism via non-Fermi-liquid state by isoelectronic chemical doping is evident in this solid solution. The heat-capacity data reveal a dominant role of Kondo compensation in the magnetically ordered state. The electrical resistivity data for $x=0.2$ and 0.3 alloys show an upturn at respective Néel temperatures, establishing the formation of a magnetism-induced pseudogap for these intermediate compositions alone as though there is a gradual Fermi surface transformation as the quantum critical point is approached.

• Received 19 October 2007

DOI:https://doi.org/10.1103/PhysRevB.77.094443