Valence band studies of the RTX (R = Pr, Nd; T = Cu, Ag, Au; X = Ge, Sn) compounds

The valence band in the RTX (R = Pr,Nd; T = Cu, Ag, Au; X = Ge, Sn) compoun ds was studied by the X-ray photoemission spectroscopy. The XPS data were c ompared with the ones calculated using the spin-polarized tight binding lin ear muffin-tin orbital (TB LMTO) method. The obtained results show that the valence bands are determined mainly by the Cu 3d, Ag 4d and Au 5d bands. T he calculation of the total energy for two models of the crystal structure: an ordered of the LiGaGe-type and a disordered one of the CaIn2-type indic ates that in the RTSn (T = Cu, Ag,Au) compounds the LiGaGe-type structure i s stable. Calculated value of the Pr magnetic moment is smaller than that o f the free Pr3+ ion value, whereas the Nd magnetic moment is equal to the f ree Nd3+ ion value. (C) 2000 Elsevier Science B.V. All rights reserved.