Magnetic properties of two new compounds: Gd₂Ni₃Si₅ and Sm₂Ni₃Si₅

Abstract

The formation of two new materials, Sm₂Ni₃Si₅ and Gd₂Ni₃Si₅, of the rare-earth series R₂M₃Si₅ (R denotes rare earth and Y) and their magnetic and transport properties are reported here. These materials crystallize in the orthorhombic U₂Co₃Si₅-type structure (space group Ibam). The magnetic susceptibility of Gd₂Ni₃Si₅ follows a Curie-Weiss behavior with an effective magnetic moment 8.1μ_B/Gd ion. The material orders antiferromagnetically at 15 K. The magnetic susceptibility of Sm₂Ni₃Si₅ exhibits a deviation from the Curie-Weiss behavior which is attributed to the low-lying excited state of Sm³⁺ ions and also to crystal-field effects. This material also orders antiferromagnetically, but at 11 K. This value of the ordering temperature does not seem to follow the de Gennes scaling with respect to that of Gd₂Ni₃Si₅.