Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 54: Magnetic Coupling Phenomena

MA 54.6: Vortrag

Freitag, 20. März 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 Pentcheva^1,4, 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.