Crystal structure and magnetism of RCr2Si2C compounds (R = La, Ce, Pr)

We have prepared polycrystalline samples of RCr2Si2C compounds with R = La, Ce, Pr, and characterized them by X-ray diffraction (XRD) and field-emission scanning electron microscopy (SEM). The as-cast compounds were found to be single-phased and isostructurally crystallizing in the CeMg2Si2-based tetragonal crystal structure. The samples were further investigated by specific-heat, magnetization and AC susceptibility measurements in the temperature range 2-350 K and in magnetic fields up to 9 T. The results suggest non-trivial magnetic ordering of the Cr sublattice in all three compounds, accompanied with ferromagnetic ordering of the Pr magnetic moments below the Curie temperature of 30 K in PrCr2Si2C and possible metamagnetism in CeCr2Si2C. The experimental evidence of Cr magnetism is corroborated by results of extended first-principles calculations based on the density functional theory (DFT). (c) 2007 Elsevier B.V. All rights reserved.