Initial Stages of the Growth of Mixed Iron-cobalt Oxides on Ru(0001)

Mixed iron-cobalt oxides have been grown on a Ru(0001) single crystal substrate by reactive molecular beam epitaxy. The growth has been followed by low-energy electron microscopy and diffraction. Chemical characterization has been performed by selected area x-ray absorption spectroscopy. As previous...

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Bibliographic Details
Authors: Martín García, Laura|||0000-0001-5743-4473, Quesada, Adrian, Pérez, Lucas|||0000-0001-9470-7987, Foerster, Michael|||0000-0002-4147-6668, Aballe, Lucía|||0000-0003-1810-8768, Figuera, Juan de la|||0000-0002-7014-4777
Format: article
Publication Date:2016
Country:España
Institution:Universitat Autònoma de Barcelona
Repository:Dipòsit Digital de Documents de la UAB
Language:English
OAI Identifier:oai:ddd.uab.cat:202507
Online Access:https://ddd.uab.cat/record/202507
https://dx.doi.org/urn:doi:10.1016/j.phpro.2016.11.075
Access Level:Open access
Keyword:Cobalt monoxide
Iron monoxide
Reactive molecular beam epitaxy
Low-energy electron microscopy
Selected area x-ray absorption
Photoemission electron microscopy
Description
Summary:Mixed iron-cobalt oxides have been grown on a Ru(0001) single crystal substrate by reactive molecular beam epitaxy. The growth has been followed by low-energy electron microscopy and diffraction. Chemical characterization has been performed by selected area x-ray absorption spectroscopy. As previously known, iron grows into a wetting layer of FeO. In contrast, cobalt grows into three-dimensional islands of CoO, of either with a (111) -most common- or a (100) orientation. For mixed compositions, flat 2D growth is regained. Depending on temperature, either segregation into two FeCo compositions or a single phase is detected. In all cases the structure corresponds to an in-plane expanded (111)-oriented halite one. When only one phase is observed or for the Co-rich phase in the two phase film, its crystal structure is rotated by 30° relative to the Ru substrate, unlike the Co-poor phase which appears aligned with the substrate.