Person: González Barrio, Miguel Ángel
Universidad Complutense de Madrid
Faculty / Institute
Física de Materiales
Ciencia de los Materiales e Ingeniería Metalúrgica
Now showing 1 - 5 of 5
- PublicationElectronic structure of reconstructed Au(100): Two-dimensional and one-dimensional surface states(American Physical Society, 2012-07-18) Bengio, S.; Navarro, V.; González Barrio, Miguel Ángel; Cortes, R.; Vobornik, I.; Michel, E. G.; Mascaraque Susunaga, ArantzazuThe clean surface of Au(100) presents a complex reconstruction characterized by a hexagonal topmost layer. We report an angle-resolved photoemission study of the electronic structure of this surface, including an analysis of the Fermi surface, combined with structural information from low-energy electron diffraction and scanning tunneling microscopy. In the complex Fermi surface map found, we identify different contributions from the bulk bands, from interface states located below the hexagonal topmost layer, and from the hexagonal topmost layer itself. The electronic states related to this layer exhibit quasi-one-dimensional character, in agreement with the chain aspect of the reconstructed layer, as demonstrated by their dispersion, periodicity, and reciprocal space location.
- PublicationHighly Bi-doped Cu thin films with large spin-mixing conductance(American Institute of Physics, 2018-10-22) Ruiz Gómez, Sandra; González Barrio, Miguel Ángel; Mascaraque Susunaga, Arantzazu; Pérez García, Lucas; Serrano, Aída; Guerrero, Rubén; Muñoz, Manuel; Lucas, Irene; Foerster, Michael; Aballe, LucíaThe spin Hall effect (SHE) provides an efficient tool for the production of pure spin currents, essentially for the next generation of spintronics devices. Giant SHE has been reported in Cu doped with 0.5% Bi grown by sputtering, and larger values are predicted for larger Bi doping. In this work, we demonstrate the possibility of doping Cu with up to 10% of Bi atoms without evidence of Bi surface segregation or cluster formation. In addition, YIG/BiCu structures have been grown, showing a spin mixing conductance larger that the one shown by similar Pt/YIG structures, reflecting the potentiality of these newmaterials.
- PublicationFormation of a magnetite/hematite epitaxial bilayer generated with low energy ion bombardment(American Institute of Physics, 2017-02-27) Ruiz Gómez, Sandra; Serrano, A.; Carabias,, I.; Garcıa, M. A.; Hernando Grande, Antonio; Mascaraque Susunaga, Arantzazu; Pérez García, Lucas; González Barrio, Miguel Ángel; Rodríguez de la Fuente, ÓscarWe have used a low-energy ion bombardment to fabricate an epitaxial single-crystalline magnetite/hematite bilayer grown on Au(111). This non-conventional fabrication method involves the transformation of the upper layers of a single-crystalline hematite thin film to single-crystalline magnetite, a process driven by the preferential sputtering of oxygen atoms and favoured by the good structural matching of both phases. We show the reversibility of the transformation between hematite and magnetite, always keeping the epitaxial and single- crystalline character of the films. The magnetic characterization of the bilayer grown using this method shows that the magnetic response is mainly determined by the magnetite thin film, exhibiting a high coercivity. Published by AIP Publishing.
- PublicationDynamics of Li deposition on epitaxial graphene/Ru(0001) islands(Elsevier Science B. V., 2022-08-15) Prieto, J.E.; González Barrio, Miguel Ángel; García Martín, E; Soria, Guiomar D.; Morales de La Garza, L.Li metal has been deposited on the surface of a Ru(0001) single crystal containing patches of monolayer-thick epitaxial graphene islands. The use of low-energy electron microscopy and diffraction allowed us to in situ monitor the process by measuring the local work function as well as to study the system in real and reciprocal space, comparing the changes taking place on the graphene with those on the bare Ru(0001) surface. It is found that Li deposition decreases the work function of the graphene islands but to a much smaller degree than of the Ru(0001) surface, as corresponds to its intercalation below the graphene overlayer. Finally, the diffusion process of Li out of the graphene islands has been monitored by photoelectron microscopy using a visible-light laser.
- PublicationLarge Dzyaloshinskii-Moriya interaction induced by chemisorbed oxygen on a ferromagnet surface(American Association for the Advancement of Science, 2020-08) Chen, Gong; Mascaraque Susunaga, Arantzazu; Jia, Hongying; Zimmermann, Bernd; Robertson, MacCallum; Lo Conte, Roberto; Hoffmann, Markus; González Barrio, Miguel Ángel; Ding, Haifeng; Wiesendanger, RolandThe Dzyaloshinskii-Moriya interaction (DMI) is an antisymmetric exchange interaction that stabilizes chiral spin textures. It is induced by inversion symmetry breaking in noncentrosymmetric lattices or at interfaces. Recently, interfacial DMI has been found in magnetic layers adjacent to transition metals due to the spin-orbit coupling and at interfaces with graphene due to the Rashba effect. We report direct observation of strong DMI induced by chemisorption of oxygen on a ferromagnetic layer at room temperature. The sign of this DMI and its unexpectedly large magnitude-despite the low atomic number of oxygen-are derived by examining the oxygen coverage-dependent evolution of magnetic chirality. We find that DMI at the oxygen/ferromagnet interface is comparable to those at ferromagnet/transition metal interfaces; it has enabled direct tailoring of skyrmion's winding number at room temperature via oxygen chemisorption. This result extends the understanding of the DMI, opening up opportunities for the chemisorption-related design of spin-orbitronic devices.