Ce₂Ni₃Si₅: a mixed-valence cerium compound

Abstract

The results of electrical resistivity (4.2–300 K), magnetic susceptibility (5300 K) and specific heat (2–20 K) are reported on the ternary orthorhombic rare-earth compound Ce₂Ni₃Si₅. 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 T² 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 χ vs T curve. Specific heat measurements (2–20 K) give a value of γ≈62 mJ/Ce mol K² which is similar in magnitude to those encountered in valence-fluctuating systems. From these observations we conclude that Ce₂Ni₃Si₅ is a Ce-based valence-fluctuation compound.