THE MAGNETIC-PROPERTIES OF GADOLINIUM HOLMIUM SUPERLATTICES/

The magnetic properties of Gd/Ho superlattices have been investigated using neutron-diffraction techniques. Between T approximate to 297 K a nd T approximate to 138 K, the magnetic moments in each Gd block order ferromagnetically in the basal plane with the moments in adjacent Gd blocks antiferromagnetically aligned. At temperatures below T approxim ate to 138 K, the Ho moments order in a basal-plane helix, while the G d moments remain ferromagnetically aligned in the basal plane with an alignment between adjacent Gd blocks that is dependent on temperature and the Ho-block thickness. The coherence lengths of the magnetic stru ctures in the growth direction range from 350 Angstrom to 800 Angstrom . Comparisons are made with the results from previous studies of heavy rare-earth superlattices.