Exchange bias in UO.sub.2./sub./Fe.sub.3./sub.O.sub.4./sub. thin films above the Néel temperature of UO.sub.2./sub

0434826 - FZÚ 2015 RIV US eng J - Journal Article
Tereshina, Evgeniya - Bao, Z. - Havela, L. - Daniš, S. - Kuebel, C. - Gouder, T. - Caciuffo, R.
Exchange bias in UO₂/Fe₃O₄ thin films above the Néel temperature of UO₂
Applied Physics Letters. Roč. 105, č. 12 (2014), "122405-1"-"122405-5". ISSN 0003-6951. E-ISSN 1077-3118
R&D Projects: GA ČR GP13-25866P
Institutional support: RVO:68378271
Keywords : exchange bias effect * uranium dioxide * magnetite
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.302, year: 2014

Exchange bias (EB) was investigated on heterostructures consisting of a stoichiometric UO2 film grown epitaxially on a LAO substrate and covered with highly textured Fe3O4 layers of variable thickness. EB reaching 2.6 kOe was observed at lowest temperatures in a bilayer with the thinnest Fe3O4. Magnetization measurements demonstrate that a remarkably large EB is present at temperatures higher than the bulk Neel temperature of UO2. The effects is complex: we suggest that it is provided both by strong exchange coupling between UO2 and Fe3O4 and by EB within magnetite. The former can be caused by proximity effects combined with a magnetic anisotropy of UO2, persisting above a continuous magnetic-ordering transformation. For magnetite, the results indicate the presence of pinned moments up to 120 K, that is a temperature of Verwey transition.
Permanent Link: http://hdl.handle.net/11104/0238813