RESUMO
An energy-dispersive X-ray absorption spectroscopy beamline mainly dedicated to X-ray magnetic circular dichroism (XMCD) and material science under extreme conditions has been implemented in a bending-magnet port at the Brazilian Synchrotron Light Laboratory. Here the beamline technical characteristics are described, including the most important aspects of the mechanics, optical elements and detection set-up. The beamline performance is then illustrated through two case studies on strongly correlated transition metal oxides: an XMCD insight into the modifications of the magnetic properties of Cr-doped manganites and the structural deformation in nickel perovskites under high applied pressure.
Assuntos
Metais/química , Óxidos/química , Síncrotrons , Espectroscopia por Absorção de Raios X/métodos , Argentina , Transferência de Energia , Estatística como AssuntoRESUMO
The remarkable polarization properties of synchrotron light have lead to the advent of modern synchrotron-related spectroscopic studies with angular and/or magnetic selectivity. Here an overview is given of the prominent aspects of the polarization of the light delivered by a bending magnet, and some dichroic properties in X-ray absorption spectroscopy (XAS). Two studies developed at the Brazilian Synchrotron Light Laboratory are then reported, exemplifying the profit gained using linear and circular polarization of X-rays for the study of magnetic thin films and multilayers. Angle-resolved XAS was used in strained manganite thin films to certify a model of local distortion limited within the MnO6 polyhedron. A pioneering experience of X-ray magnetic scattering at grazing incidence associated with dispersive XAS in a Co/Gd multilayer draws new perspectives for magnetic studies in thin films and multilayers under atmospheric conditions in the hard X-ray range.