CE2NI3SI5 - A MIXED-VALENCE CERIUM COMPOUND

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 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 chi vs T curve. Specific heat measurements (2-20 K) give a value of gamma almost-equal-to 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.