Magnetic properties and electronic structure of YxGd1-xNi5 compounds

Measurements of the magnetic susceptibility, crystal and electronic structure for YxGd1-xNi5 (x = 0.0, 0.2, 0.5, 0.8, 1.0) compounds with a CaCu5-type crystal structure are reported. The substitution of Y for Gd atoms results in a decrease of the unit cell volume and Curie temperature. In the paramagnetic range (300-650 K), the DC susceptibility follows the Curie-Weiss law for all investigated compounds. The effective moment deduced from the Curie constant decreases rapidly with Y concentration. The saturation magnetic moment for GdNi5 exhibits a negative polarization of the Ni3d band, induced by interactions with Gd5d states. Both valence band and core level X-ray photoelectron spectra are analysed. The presence of satellite structure in the Ni2p core level suggests that the magnetic polarisation of Ni3d states, which dominates the valence band in all investigated compositions. The experimental investigations were complemented by the band,structure calculations. In all cases, the calculations were based on the KKR and KKR-CPA methods. Satisfactory agreement between the recorded spectra and those obtained from the calculated electronic structure was achieved.