X-RAY MAGNETIC CIRCULAR-DICHROISM AT THE GD-L EDGES IN GD-NI-CO AMORPHOUS SYSTEMS

X-ray magnetic circular dichroism (XMCD) experiments have been perform ed at the L(2,3) edges of gadolinium in the amorphous Gd-Ni-Co and Gd- Ni alloys in order to observe the effect of the transition metal on th e polarization of the rare-earth 5d band. The magnetic properties of t he Gd-Ni-Co alloys, weak anisotropy or perpendicular easy axis of magn etization, are very well suited to XMCD experiments and very large XMC D signals are observed at the Gd L(2,3) edges. The signals corrected f rom the circular polarization rate (P-c=0.65) can reach up to -22% at the L(2) and +11% at the L(3) for some samples. The V-Like behavior of the XMCD signal at the Gd L edges near the compensation temperature i s understood in terms of distribution of the Co concentration in the G d-Ni-Co sputtered films. Within the spin-dependent radial matrix model , the evolution of the XMCD intensity in the Gd-Ni-Co films as a funct ion of the Co concentration qualitatively accounts for the variation o f the spin-dependent final-state density Delta rho/rho monitored by th e Co concentration.