Ce2Ni3Si5: A mixed-valence cerium compound.

Abstract

The results of electrical resistivity (4.2--300 K), magnetic susceptibility (5--300 K) and specific heat (2--20 K) are reported on the ternary orthorhombic rare-earth compound ${\mathrm{Ce}}_{2}$${\mathrm{Ni}}_{3}$${\mathrm{Si}}_{5}$. The resistivity of the material is nearly temperature independent above 120 K unlike that of a normal metallic material. The magnetic contribution to resistivity shows a broad maximum around 200 K. At low temperatures, the resistivity follows a ${\mathit{T}}^{2}$ behavior in the temperature range 4--13 K. The inverse magnetic susceptibility deviates from Curie-Weiss behavior below 80 K where it exhibits a broad maximum in the \ensuremath{\chi} vs T curve. Specific heat measurements (2--20 K) give a value of \ensuremath{\gamma}\ensuremath{\approxeq}62 mJ/Ce mol ${\mathrm{K}}^{2}$ which is similar in magnitude to those encountered in valence-fluctuating systems. From these observations we conclude that ${\mathrm{Ce}}_{2}$${\mathrm{Ni}}_{3}$${\mathrm{Si}}_{5}$ is a Ce-based valence-fluctuation compound.