Crystalline electric field parameters for RTX2 compounds

The RTxX2(x≤1) type metallic compounds where R is a rare-earth element, T is a d-electron element and X is a p-electron element (X = Si, Ge, Sn) crystallize in different orthorhombic crystal structures. The systems exhibit complex magnetic behaviour. Their magnetism arises from the long range interaction of the magnetic moments localized on the rare-earth ions, described by RKKY model. The magnetic ordering in these systems is not purely of the RKKY-type but is modified by the crystalline electric field effect, which can significantly influence the magnitude of the Neel temperature and decrease the rare-earth magnetic moments as compared with the free ion values. The determination of the CEF parameters is important for understanding the nature of magnetic properties of intermetallic compounds. The Bnm parameters were calculated for RTX2 compounds using the so-called point-charge model. The quadrupole splitting observed in the Moessbauer spectra of GdTxSn2 compounds (T = Fe, Co, Ni, Cu) allow to determined the experimental values of B20 parameters for RTX2 compounds