Quantitative magnetic imaging at the nanometer scale by ballistic electron magnetic microscopy

Hervé, Marie; Tricot, Sylvain; Guézo, Sophie; Delhaye, Gabriel; Lépine, Bruno; Schieffer, Philippe; Turban, Pascal

doi:10.1063/1.4811690

Cited by 6 publications

(10 citation statements)

References 18 publications

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“…The solid lines indicate the surface as it really is, where the dashed lines show what the detector actually sees. However researchers have found ways to contain it, minimize its effects, or even make use of it, e.g., for magnetic imaging, 17 nanowires, 18,19 for multilayer deposition 20 and surface growth, [21][22][23][24] and meteorite photometry. 25 But still, we have a lot to learn in various aspects of this phenomenon.…”

Section: Introductionmentioning

confidence: 99%

How shadows shape our impression of rough surfaces

Salami

Hajian

Fazeli

et al. 2014

Journal of Applied Physics

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Articles you may be interested inDrop splashing on a rough surface: How surface morphology affects splashing threshold Appl. Phys. Lett.Shape of a large drop on a rough hydrophobic surface Phys. Fluids 25, 022102 (2013); 10.1063/1.4789494 Examination of coherent surface reflection coefficient (CSRC) approximations in shallow water propagationThe aim here is to shape our impression of rough surfaces based on the formation of shadows. The shadows blackout some parts of the surface leading us to state that rough surfaces are not always quite the way they seem. In fact, it is the angle of view that proves the size of the shadows. In surface profilometry, the scanned image is produced by a vertical shot. While in nature, a vertical sighting of events is not always possible or preferred, therefore readings by various observers would depend on the angle of their line of sight. In the present work, owing to the statistical properties of rough surfaces, the relation between a vertical and angular line of site view of a surface is obtained. This enables the estimation of how the surface really looks like, even though the observer has an non vertical line of sight. To be most illustrative, a comparison between wave scattering from an actual surface and that from an observed surface is performed. The shadowing effects which are shown to be inversely proportional to the Hurst exponent, cause the height correlation function to posses a bi-scaling behaviour. We also illustrate how the correlation develops its efficiency as the line of sight angle tends to zero, making the surface look smooth. V C 2014 AIP Publishing LLC. [http://dx.

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Section: Introductionmentioning

confidence: 99%

How shadows shape our impression of rough surfaces

Salami

Hajian

Fazeli

et al. 2014

Journal of Applied Physics

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“…This scheme has been motivated by the availability of experimental data on ultra-thin samples, like those reported in Refs [6,7].…”

Section: Conclusion and Future Perspectivesmentioning

confidence: 99%

“…Instead, a typical GMR device consists of intercalated magnetic and non-magnetic layers of few nanometers and is not well described by a semi-infinite slab [7]. To overcome this difficulty, we have developed a model for epitaxial heterostructures based on a layer-by-layer construction of the Hamiltonian, which deals with layered heterostructures of any composition and width.…”

Section: Introductionmentioning

confidence: 99%

“…Second, spin-resolved electron currents are currently thoroughly investigated in epitaxial structures for their applications in giant magnetoresistance (GMR) devices. Significant advances in the study of magnetotransport phenomena at the nanometer scale through thin magnetic heterostructures have recently been obtained using Ballistic Electron Emission Microscopy (BEEM) [6,7]. BEEM is an extension of Scanning Tunneling Microscopy (STM) conceived to study metal-semiconductor interfaces [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Electron transport in ultra-thin films and ballistic electron emission microscopy

Claveau

Matteo

Andrés

2017

J. Phys.: Condens. Matter

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Abstract. We have developed a calculation scheme for the elastic electron current in ultra-thin epitaxial heterostructures. Our model uses a Keldysh's non-equilibrium Green's function formalism and a layer-by-layer construction of the epitaxial film. Such an approach is appropriate to describe the current in a Ballistic Electron Emission Microscope (BEEM) where the metal base layer is ultra-thin and generalizes a previous one based on a decimation technique appropriated for thick slabs. This formalism allows a full quantum mechanical description of the transmission across the epitaxial heterostructure interface, including multiple scattering via the Dyson equation, which is deemed a crucial ingredient to describe interfaces of ultra-thin layers properly in the future.We introduce a theoretical formulation needed for ultra-thin layers and we compare with results obtained for thick Au(111) metal layers. An interesting effect takes place for a width of about ten layers: a BEEM current can propagate via the center of the reciprocal space (Γ) along the Au(111) direction. We associate this current to a coherent interference finite-width effect that cannot be found using a decimation technique. Finally, we have tested the validity of the handy semiclassical formalism to describe the BEEM current.

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“…Further details on samples growth can be found elsewhere. 9 In the following, all crystalline directions will refer to crystal directions of the GaAs(001) substrate. Electrochemically etched W STM tips are cleaned in situ by thermal heating before the BEMM experiments.…”

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confidence: 99%

k-space spin filtering effect in the epitaxial Fe/Au/Fe/GaAs(001) spin-valve

Hervé¹,

Tricot²,

Claveau³

et al. 2013

Appl. Phys. Lett.

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International audienceThe hot-electron magnetotransport of epitaxial Fe/Au/Fe/GaAs(001) spin-valves is investigated by ballistic-electron magnetic microscopy. A magnetocurrent amplitude larger than 500% is observed at room temperature close to the Schottky barrier energy. Remarkably, this magnetocurrent is not significantly affected by the thickness reduction of ferromagnetic films, down to 5 atomic layers of the Fe(001) top electrode. This rather suggests a dominant interfacial spin-filtering effect. Finally, the magnetocurrent is strongly reduced when the effective mass of the semiconductor collector is increased. These observations are consistent with recent theoretical prediction of k-space spin-filtering effect in epitaxial spin-valves attached to a semiconducting lead

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Quantitative magnetic imaging at the nanometer scale by ballistic electron magnetic microscopy

Cited by 6 publications

References 18 publications

How shadows shape our impression of rough surfaces

How shadows shape our impression of rough surfaces

Electron transport in ultra-thin films and ballistic electron emission microscopy

k-space spin filtering effect in the epitaxial Fe/Au/Fe/GaAs(001) spin-valve

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