CaF2-based UO2/Fe3O4 thin films: crystal structure and magnetic exchange bias effect

0469816 - FZÚ 2017 RIV US eng A - Abstract
Tereshina, Evgeniya - Bao, Z. - Havela, L. - Macková, Anna - Gouder, T. - Caciuffo, R.
CaF2-based UO2/Fe3O4 thin films: crystal structure and magnetic exchange bias effect.
2015 IEEE International Magnetics Conference (INTERMAG). Piscataway: IEEE Inc., 2015. AG-10. ISBN 978-1-4799-7321-7.
[IEEE International Magnetics Conference (Intermag) 2015. 11.05.2015-15.05.2015, Peking]
R&D Projects: GA ČR GP13-25866P
Institutional support: RVO:68378271 ; RVO:61389005
Keywords : exchange bias * magnetite * uranium dioxide
Subject RIV: BM - Solid Matter Physics ; Magnetism; BG - Nuclear, Atomic and Molecular Physics, Colliders (UJF-V)

We studied the crystal structure and magnetic exchange bias (EB) effect in bilayers of an antiferromagnetic UO2 with a ferrimagnetic Fe3O4. The samples were grown on CaF2 (100) and (111) substrates. Magnetic hysteresis loops obtained after field cooling in a magnetic field of 20 kOe showed strong exchange bias with the maximum effect reaching 1.6 kOe at 5 K for the UO2/Fe3O4 sample with the thinnest magnetite layer of tFM = 80 Å (CaF2 (100) substrate). The EB obtained for the same sample on a CaF2 [111] was found to be of 25% higher. Similar trend was found in the samples with larger tFM’s. Interestingly, exchange bias did not vanish at the bulk Néel temperature of UO2. Non-zero values of EB were observed up to 125 K. This is in line with our previous study of the LaAlO3-based UO2/Fe3O4 system, where exchange bias disappeared at the Verwey transition temperature in magnetite.

Permanent Link: http://hdl.handle.net/11104/0267604