Magnetic ordering in a (001) Sm layer and a Sm/Y superlattice studied by resonant x-ray magnetic scattering

The magnetic ordering of samarium in a 5000 Angstrom thick (001) Sm film and in a (001) Sm/Y superlattice has been investigated using resonant x-ray magnetic scattering at the samarium L-3 edge. In both samples, the hexagonal sublattice orders below T-N = 106 K. Magnetic resonances of dipolar and quadrupolar origin are observed above and below the edge respectively and allow one to study the 5d and 4f magnetism separately. In the film, the cubic sublattice also shows long range magnetic order below 12 K. The relative contributions of the 4f and 5d electrons to the magnetic moments on the hexagonal sites are the same for T < 12 K, 12 K < T < T-N and close to TN. In the superlattice, the Y and Sm layers mainly retain their own bulk crystallographic structure (i.e. hcp and 'Sm structure' respectively). The hexagonal sublattice of the Sm layers shows the same magnetic structure as in the thick firm, but the energy dependence of the resonance is different. There is no coherence of the magnetic structure through the Y spacer layers.