POLARIZED NEUTRON REFLECTION STUDY OF GD W MULTILAYERS/

Magnetic properties of a series of Gd/W multilayers with constant W-la yer thickness (18 Angstrom) and variable Gd-layer thickness have been studied by polarized neutron reflectometry and SQUID magnetometry. Our results are not consistent with enhanced Gd moments and/or strong fer romagnetic spin polarizations in the W layers as claimed by Heys et al . [1]. As an unexpected and remarkable feature we have observed ed for the multilayers with thin Gd films of 14 and 19 Angstrom strong unusu al peaks in the reflectivity spectra which depend on the external magn etic field and on the cooling process. These peaks depend on the magne tic structure of the layer system and do not occur in multilayers with thicker Gd films.