X-ray magnetic circular dichroism of Gd/Fe multilayers

Gd(t nm)/Fe(t nm) multilayers in the range of 0.25 less than or equal to t less than or equal to 5 were prepared by rf magnetron sputtering. The structural analysis showed that the multilayers have compositional modulation for bilayer periods of Lambda greater than or equal to 1 nm, and have rather uniform alloy structure for Lambda = 0.5 nm, From an estimation using the X-ray sum rule, rather large Fe and Gd orbital moments of 0.4 and 0.16 mu (B), respectively, were obtained in the multilayer with Lambda = 1 nm, The quite small Fe spin moment observed in the multilayers for Lambda = 5.0 and 10.0 nm, together with the structural analysis, suggests the existence of an amorphous Fe layer having a spin glass like magnetic structure, which is known for YFe and LuFe alloys.