Crystal-field-induced magnetic frustration in NdMIn5 and Nd2MIn8 (M = Rh, Ir) antiferromagnets

We have synthesized the series of compounds NdMIn5 and Nd2MIn8 in single cr ystal form, where M = Rh or Lr. These materials form in tetragonal derivati ves of the Cu3Au-structure NdIn3 compound. Messurements of magnetic suscept ibility, electrical resistivity, and low-temperature heat capacity are repo rted. These compounds order antiferromagnetically at low temperature (T-N<1 4 K) and the evolution of their magnetic properties depends on the crystal- field ground-state configuration. Comparison between the present data and m agnetic properties of the isostructural new heavy fermion compounds Ce(Rh,I r)In-5 and Ce-2(Rh,Ir)In-8 suggests that crystal field effects and magnetic anisotropy should be taken into account to understand the rich phase diagr am of these compounds.