Crystal growth, structure, and physical properties ofLn(Ag, Al, Si)2 (Ln = Ce and Gd)

Abstract

Single crystals of CeM2 and GdM2 (M = Ag, Al, and Si) were grown by the flux growth technique and characterized by means of singlecrystal x-ray diffraction, magnetic susceptibility, resistivity, and heat capacity measurements.CeM2 andGdM2 crystallize in the tetragonalI41/amd space group with theα-ThSi2 structure type withlattice parameters a ∼ 4.2 Å and c ∼ 14.4 Å. Curie–Weiss behavior is observed for both analogues withCeM2 ordering first ferromagnetically at 11 K with a second antiferromagnetic transition at 8.8 K whileGdM2 orders antiferromagnetically at 24 K. Heat capacity measurements onCeM2 show two magnetic transitions at 10.8 and 8.8 K with an electronic specific heat coefficient,γ0, of ∼ 53 mJ K − 2 mol − 1. The entropy at the magnetic transition is less than the expectedRln2 forCeM2, reinforcing the assertions of an enhanced mass state and Kondo behavior being observedin the resistivity.