Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure

J. Phys. IV France 7 (1997) C2-447-C2-448
DOI: 10.1051/jp4/1997046

Effects of Spin-Dependent Spectral Weight on Magnetic Circular X-Ray Dichroism: Application to R(Ni_xCo_1-x)₅ Intermetallic Compounds

R. M. Galéra¹, S. Pizzini^{1, 0}, J.A. Blanco², J.P. Rueff¹, A. Fontaine¹, Ch. Giorgetti³, F. Baudelet³, E. Dartyge³ and M.F. Lopez<sup>3

1</sup>  Laboratoire de Magnétisme Louis Néel Laboratory associated with the Université Joseph Fourier de Grenoble., CNRS, BP. 166X, 38042 Grenoble cedex 9, France
²  Dermanent address : Dpto. de Fisica, Universidad de Oviedo, 33006 Oviedo, Spain.
³  LURE, bâtiment 209d, Centre Universitaire Paris-Sud, 91405 Orsay cedex, France

Abstract
Systematic study of the RE(Ni_xCo_1-x)5 compounds (RE=La, Gd and Tb) has allowed to investigate the combined effects of the 3d-5d hybridization and 4f-5d exchange on the RE L_2,3-edge MCXD signal. In La(Ni_xCo_1-x)5 compounds, where the Sd polarization results only from the hybridization between the 5d and 3d bands, the MCXD signal scales with the Sd moment and can be explained by a one-particle model for the absorption process [1-3]. When only the 4f-5d exchange intervenes, like in the GdNi₅ and TbNi₅ compounds, its effects on the MCXD sign and amplitude are very important, they are understood in term of spin-dependence of the radial matrix elements. When both the 3d-5d hybridization and the 4f-5d exchange are present like in the Tb(Ni_xCo_1-x)5 compounds, the amplitude variations of the L_2,3-edge MCXD spectra may be qualitatively descripted by a balanced contribution of both effects.

© EDP Sciences 1997