Antiferromagnetic behavior in CeCo9Ge4

Abstract

We investigate the novel intermetallic ternary compounds RCo 9Ge4 with R = La and Ce by means of X-ray diffraction, susceptibility and specific heat measurements. CeCo9Ge4 crystallizes in the space group I4/mcm and is characterized by the coexistence of two different magnetic sublattices. The Ce-based sublattice, with an effective moment close to the expected value for a Ce3+-ion, exhibits a magnetically ordered ground state with TN = 12.5K. The Co-based sublattice, however, exhibits magnetic moments due to itinerant 3d electrons. The magnetic specific heat contribution of the Ce-sublattice is discussed in terms of a resonance-level model implying the interplay between an antiferromagnetic phase transition and the Kondo-effect and an underlying Schottky-anomaly indicating a crystal field level scheme splitting into three twofold degenerated micro states (Δ1 = 69K, Δ2 = 133 K). © 2010 IOP Publishing Ltd.