Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 54: Magnetic Coupling Phenomena
MA 54.6: Talk
Friday, March 20, 2015, 10:45–11:00, EB 301
Room temperature ferromagnetism in CoO/Co3O4 nanocrystals — •Zi-An Li1, Nerio Fontaíña-Troitiño2, András Kovács3, Sara Liébana-Viñas1, Marina Spasova1, Rafal E. Dunin-Borkowski33, Markus Müller4, David Doennig4, Rossitza Pentcheva1,4, Michael Farle1, and Veronica Salgueiriño2 — 1Faculty of Physics and Center for Nanointegration (CENIDE), University Duisburg-Essen,Germany — 2Departamento de FísicaAplicada, Universidade de Vigo, Spain — 3Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Research Centre Jülich, Germany — 4Department of Earth and Environmental Sciences, Section Crystallography, LMU Munich, Munich, Germany
Hetero-interfaces formed between oxide perovskite structures can exhibit novel functionality that is not available in the bulk constituents. Here, we present a detailed high-resolution transmission electron microscopy and quantitative magnetometry study of a robust (above room temperature) environmentally-stable ferromagnetically-coupled interface layer, which forms between the antiferromagnetic rocksalt CoO cores and the surrounding 2-4 nm-thick antiferromagnetic spinel Co3O4 surface layers of octahedral nanocrystals [1, 2]. The origin of the experimentally observed ferromagnetic phase is discussed based on density functional theory calculations including a Hubbard U term.
References 1. N. Fontaina-Troitino et al. Nano Letters 14, 640 (2014) 2. Financial support by the European Research Council Grant *IMAGINE* and SFB/TR80 is gratefully acknowledged.