Magnetic Ordering and Resonance Process in Sm Epitaxial Films and Superlattices: An RXMS Study

Abstract

Resonant x-ray magnetic scattering (RXMS) may be considered as an atomic species and electronic shell selective, probe of magnetism in solids. Magnetic ordering of samarium in a (001)Sm film and a (001)Sm/Y superlattice has been investigated at the samarium L₃ and L₂ edges. In both samples, the hexagonal sublattice orders below the Néel temperature T _N =106 K. Magnetic resonances of dipolar and quadrupolar origin are observed above and below the edge respectively and allow to study the 5d and 4f magnetism separately. The ratio between the two contributions to the magnetic moments remains constant, even close to T _N. In the film, the cubic sublattice also shows long range magnetic order below 12K. The energy line shapes of the resonances are discussed in terms of the introduction of collective effects (band structure of the 5d level) into the single-ion model. In the superlattice, the energy dependence of the resonance is different from the film one.