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- Devishvili, A., et al.
(författare)
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SuperADAM : Upgraded polarized neutron reflectometer at the Institut Laue-Langevin
- 2013
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 84:2, s. 025112-
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Tidskriftsartikel (refereegranskat)abstract
- A new neutron reflectometer SuperADAM has recently been built and commissioned at the Institut Laue-Langevin, Grenoble, France. It replaces the previous neutron reflectometer ADAM. The new instrument uses a solid state polarizer/wavelength filter providing a highly polarized (up to 98.6%) monochromatic neutron flux of 8 x 10(4) n cm(-2) s(-1) with monochromatization Delta lambda/lambda = 0.7% and angular divergence Delta alpha = 0.2 mrad. The instrument includes both single and position sensitive detectors. The position sensitive detector allows simultaneous measurement of specular reflection and off-specular scattering. Polarization analysis for both specular reflection and off-specular scattering is achieved using either mirror analyzers or a He-3 spin filter cell. High efficiency detectors, low background, and high flux provides a dynamic range of up to seven decades in reflectivity. Detailed specifications and the instrument capabilities are illustrated with examples of recently collected data in the fields of thin film magnetism and thin polymer films.
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| 2. |
- Fraerman, A. A., et al.
(författare)
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Magnetic force microscopy of helical states in multilayer nanomagnets
- 2008
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:7, s. 073916-
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Tidskriftsartikel (refereegranskat)abstract
- We have used magnetic force microscopy (MFM) to investigate noncollinear helical states in multilayer nanomagnets, consisting of a stack of single domain ferromagnetic disks separated by insulating nonmagnetic spacers. The nanomagnets were fabricated from a [Co/Si]x3 multilayer thin film structure by electron beam lithography and ion beam etching. The structural parameters (Co layer and spacer thicknesses) were optimized to obtain a clear spiral signature in the MFM contrast, taking into account the magnetostatic interaction between the layers. MFM contrast corresponding to the helical states with different helicities was observed for the optimized structure with Co layer thicknesses of 16, 11, and 8 nm, and with 3 nm Si spacer thickness.
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| 3. |
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| 4. |
- Hellwig, M. Ay. O, et al.
(författare)
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Oxidation of epitaxial Y(0001) films
- 2008
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 254:10, s. 3184-3190
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the oxidation behavior of MBE grown epitaxial Y(0 0 0 1)/Nb(1 1 0) films on sapphire (11 (2) over bar0) substrates at elevated temperatures under atmospheric conditions with a combination of experimental methods. At room temperature X-ray diffraction (XRD) reveals the formation of a 25 A thick YOxHx layer at the surface, while simultaneously oxide growth proceeds along defect lines normal to the film plane, resulting in the formation of a single crystalline cubic Y2O3 (2 2 2) phase. Furthermore, nuclear resonance analysis (NRA) reveals that hydrogen penetrates into the sample and transforms the entire Y film into the hydride YH2 phase. Additional annealing in air leads to further oxidation radially out from the already existing oxide channels. Finally material transport during oxidation results in the formation of conically shaped oxide precipitations at the surface above the oxide channels as observed by atomic force microscopy (AFM).
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| 6. |
- Kravtsov, E, et al.
(författare)
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Fine-tuning of the spin-density-wave state in Cr/V heterostructures via hydrogen uptake
- 2009
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 21:33, s. 336004-
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Tidskriftsartikel (refereegranskat)abstract
- We show that the magnetic state in rather thick Cr films can be finely tuned via hydrogen uptake into adjacent vanadium layers at rather low hydrogen pressures. By changing the hydrogen concentration and, hence, the electronic structure in the V layers, it is possible to affect the global properties of spin-density waves (SDWs) in Cr layers, including the SDW period and the Neel temperature. We provide direct experimental evidence that hydrogen uptake into V layers can be used to switch between incommensurate and commensurate SDW states in a reproducible way.
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