title: High Temperature Ferromagnetism in a GdAg2 Monolayer.
abstract: Materials that exhibit ferromagnetism, interfacial stability, and tunability are highly desired for the realization of emerging magnetoelectronic phenomena in heterostructures. Here we present the GdAg2 monolayer alloy, which possesses all such qualities. By combining X-ray absorption, Kerr effect, and angle-resolved photoemission with ab initio calculations, we have investigated the ferromagnetic nature of this class of Gd-based alloys. The Curie temperature can increase from 19 K in GdAu2 to a remarkably high 85 K in GdAg2. We find that the exchange coupling between Gd atoms is barely affected by their full coordination with noble metal atoms, and instead, magnetic coupling is effectively mediated by noble metal-Gd hybrid s,p-d bands. The direct comparison between isostructural GdAu2 and GdAg2 monolayers explains how the higher degree of surface confinement and electron occupation of such hybrid s,p-d bands promote the high Curie temperature in the latter. Finally, the chemical composition and structural robustness of the GdAg2 alloy has been demonstrated by interfacing them with organic semiconductors or magnetic nanodots. These results encourage systematic investigations of rare-earth/noble metal surface alloys and interfaces, in order to exploit them in magnetoelectronic applications.
authors.affiliation: Universidad del País Vasco , Dpto. Física Aplicada I, E-20018 San Sebastián, Spain.|IPCMS, CNRS UMR 7504, Université de Strasbourg , 67034 Strasbourg, France.
authors.forename: M
authors.initials: M
authors.lastname: Ormaza
authors.affiliation: Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , 35032 Marburg, Germany.|Donostia International Physics Center , E-20018 Donostia-San Sebastián, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Fernández
authors.affiliation: Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center , E-20018 San Sebastián, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Ilyn
authors.affiliation: Universidad del País Vasco , Dpto. Física Aplicada I, E-20018 San Sebastián, Spain.|Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center , E-20018 San Sebastián, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Magaña
authors.affiliation: Université de Liège , Institut de Physique and European Theoretical Spectroscopy Facility (ETSF), allée du 6 août, 17 Sart-Tilman, B-4000 Liège, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Xu
authors.affiliation: Université de Liège , Institut de Physique and European Theoretical Spectroscopy Facility (ETSF), allée du 6 août, 17 Sart-Tilman, B-4000 Liège, Belgium.
authors.forename: M J
authors.initials: MJ
authors.lastname: Verstraete
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, Bellaterra, 08193 Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Gastaldo
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, Bellaterra, 08193 Barcelona, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Valbuena
authors.affiliation: ALBA Synchrotron Light Source , Carretera BP 1413 km 3.3, E-08290 Cerdanyola del Vallès, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Gargiani
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, Bellaterra, 08193 Barcelona, Spain.|ICREA, Institució Catalana de Recerca i Estudis Avançats , Lluis Companys 23, 08010 Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Mugarza
authors.affiliation: Donostia International Physics Center , E-20018 Donostia-San Sebastián, Spain.|Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center , E-20018 San Sebastián, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Ayuela
authors.affiliation: Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center , E-20018 San Sebastián, Spain.|Ikerbasque, Basque Foundation for Science , 48013 Bilbao, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Vitali
authors.affiliation: Donostia International Physics Center , E-20018 Donostia-San Sebastián, Spain.|Universidad del País Vasco , Dpto. Física Materiales, E-20018 San Sebastián, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Blanco-Rey
authors.affiliation: Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , 35032 Marburg, Germany.|Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center , E-20018 San Sebastián, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Schiller
authors.affiliation: Universidad del País Vasco , Dpto. Física Aplicada I, E-20018 San Sebastián, Spain.|Donostia International Physics Center , E-20018 Donostia-San Sebastián, Spain.|Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center , E-20018 San Sebastián, Spain.
authors.forename: J E
authors.initials: JE
authors.lastname: Ortega
keywords: Ferromagnetic monolayer; high Curie temperature; nanotemplate