A5026658607- Magnetic properties of thin films
- Magnetic Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- Theoretical and Computational Physics
- Advanced Condensed Matter Physics
- ZnO doping and properties
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Anodic Oxide Films and Nanostructures
- Characterization and Applications of Magnetic Nanoparticles
- Copper Interconnects and Reliability
- Geomagnetism and Paleomagnetism Studies
- X-ray Diffraction in Crystallography
- Semiconductor materials and devices
- Nanoporous metals and alloys
- Advanced X-ray Imaging Techniques
- Magneto-Optical Properties and Applications
- Crystallization and Solubility Studies
- Copper-based nanomaterials and applications
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Physics and Applications
- GaN-based semiconductor devices and materials
- Ion-surface interactions and analysis
- Metal and Thin Film Mechanics
- Metallic Glasses and Amorphous Alloys
Institut Néel
2013-2025
Université Grenoble Alpes
2017-2024
Centre National de la Recherche Scientifique
1997-2022
Institut polytechnique de Grenoble
2022
Interface (United States)
2009-2019
Université Joseph Fourier
2009-2011
National Academy of Sciences of Belarus
2009
Spintronique et Technologie des Composants
2002-2004
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2001-2004
CEA Grenoble
2001-2004
We have fabricated ${\mathrm{C}\mathrm{o}/\mathrm{A}\mathrm{l}}_{2}{\mathrm{O}}_{3}/\mathrm{C}\mathrm{o}$ tunnel junctions in which the ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ layer includes a unique of small and disconnected cobalt clusters, with typical mean diameter ranging from 2.0 to 4.0 nm. observe spin-dependent tunneling properties with, below about 50 K, Coulomb-blockade effects induced by intermediate electron into clusters. The magnetoresistance ratio is approximately same regime...
By measuring the extraordinary Hall effect on a series of naturally oxidized Pt3 nm/Co90Fe10 0.6 nm/Al tAl samples with 0<tAl<1.2 nm, first crossover from in-plane to perpendicular magnetic anisotropy is observed when varied 0 0.2 nm. The CoFe magnetization remains out plane for 0.2<tAl<0.5 When Al thickness further increased, second back in takes place. In which kept constant, same behavior as time exposure an oxygen plasma varied. results clearly indicate that...
We study the magnetic properties of spherical Co clusters with diameters between 0.8 nm and 5.4 (25 to 7500$ atoms) prepared by sequential sputtering Al2O3. The particle size distribution has been determined from equilibrium susceptibility magnetization data it is compared previous structural characterizations. activation energies was independently obtained a scaling plot ac susceptibility. Combining these two distributions we have accurately effective anisotropy constant Keff. find that...
Polarized x-rays allow for imaging birefringent or dichroic properties of materials with nanometric resolution. To disentangle these from the electronic density, either a polarization analyzer several measurements different polarizations (typically two more) are needed. Here we demonstrate that ptychography can single measurement by using multimodal analysis. This new method provides an alternative to obtain polarization-resolved images sample when manipulating incident is not possible...
We have prepared spin valves exhibiting perpendicular magnetic anisotropy [perpendicular (PSVs)] by sputtering. These PSVs associate a “free” (Co/Pt) multilayer with “pinned” (Co/Pt)/FeMn separated various spacer materials (Pt, Cu, Al2O3). carried out comprehensive study of the and magnetotransport properties biased multilayers complete valves. When number repeats in exchange-biased is larger than 3, samples present 100% remnant magnetization configuration. The major hysteresis cycles...
By sequential deposition of thin layers cobalt and alumina by sputtering, we have fabricated granular multilayers consisting successive planes nanosized clusters separated along the growth direction. Combining grazing-incidence small-angle x-ray scattering transmission electron microscopy experiments, show that, in a given range thickness, vertical arrangement from plane to is not random but shows topology-induced self-organization.
An in-plane perpendicular magnetic coupling between Ni80Fe20 and Co has been found in NiFe/NiO/Co trilayers for a NiO thickness ranging from 4 to 25 nm by magneto-optical Kerr effect x-ray circular dichroism measurements. In the easy magnetization direction of layer, coercive field H(C) increases when layer t(NiO) increases. Because coupling, is always larger than NiO/Co bilayers with same thicknesses. The saturation NiFe H(S) decreases increases, indicating weakening coupling. Numerical...
The authors present a new tomographic technique, based on Fourier transform holography. It is lensless imaging technique to retrieve the object of interest from its diffraction pattern in single step computation. A combination dual-axis projections provides 3D vectorial magnetic image an 800-$n\phantom{\rule{0}{0ex}}m$-thick Fe/Gd multilayer 5-$\ensuremath{\mu}\phantom{\rule{0}{0ex}}m$-diameter field view with resolution 80 $n\phantom{\rule{0}{0ex}}m$. reconstruction reveals not only...
Dynamic magnetization reversal measurements have revealed a strong dependence of the exchange-coupling strength on maximum applied field for NiO/Co bilayers. Time-resolved Kerr measurements, performed at room temperature, show that coercive increases linearly with between two reversals. If is different in positive and negative directions, an exchange bias observed as well asymmetry behavior sides hysteresis loop. X-ray magnetic circular dichroism Ni ${L}_{2,3}$ edges indicate these effects...
From structural analysis by x-ray diffraction, Rutherford backscattering spectroscopy, and physical investigations (magnetization resistance), reactive sputtering assisted microwave multidipolar plasma appears to be a powerful means for tailoring the stoichiometry of transition metal nitrides. Reactive sputtered nitride Ni layers were elaborated while keeping Ar partial pressure constant (∼1.5 μbar) varying N2 in 0.1–0.5 μbar range. A mixing Ni2N Ni3N single-phase are stabilized thin high...
Cu/Co/Cu trilayers have been deposited on nanoporous alumina membranes. Magnetic properties of the resulting Co antidot arrays are investigated using SQUID magnetometry. Hysteresis loops these show two-step magnetization reversal. In addition, exchange bias is observed, whether cooling field applied within or perpendicular to surface plane. former case, changes sign close blocking temperature, and becomes positive. We attribute effects local, crescent shape films, induced by morphology This...
We have studied the electric and magnetotransport properties of $\mathrm{Co}//{\mathrm{Al}}_{2}{\mathrm{O}}_{3}/{\mathrm{Co}}_{\mathrm{I}}/{\mathrm{Al}}_{2}{\mathrm{O}}_{3}//(\mathrm{Co}or\mathrm{Cu})$ tunnel double junctions, in which intermediate ${\mathrm{Co}}_{I}$ layer is either granular or percolated clusters top electrode Co Cu. In spin-dependent tunneling with Coulomb-blockade effect was observed. The temperature dependence resistance can be attributed to two conduction channels...
There exists a controversy in the literature concerning values of coercive and bias fields antidots magnetic structures formed by hexagonal network nanoholes. The (HC) exchange (∣HEXC∣) for (deposited on ultrathin anodic aluminum oxide, namely, AAO) are either increased or diminished comparison with same nanostructures grown continuous substrates (namely, CML). We propose to elucidate these debates showing importance easy axis magnetization, direction applied field, thicknesses layers,...
We present an ab initio numerical tool to simulate surface resonant X-ray diffraction experiments. The crystal truncation rods and the spectra around a given absorption edge are calculated at any position of reciprocal space. Density functional theory is used determine scattering factor atom within its local environment calculate peak intensities for surfaces covered with thin film or one several adsorbed layers. Besides sample geometry, collected data also depend on parameters, such as beam...
Real time dynamic magnetization reversal measurements at room temperature have been performed on polycrystalline exchange-coupled NiO/Co bilayers over 10 decades of applied field sweep rates. Domain wall displacement and domain nucleation regimes govern the low high rates, respectively. The crossover between two depends relative thickness layers. Thicker Co favors propagation, whereas thicker NiO nucleation. coupling energy interface was found to be inversely proportional square root area...
We report on the evolution of structure and composition a Pt(3 nm)/Co(0.6 nm)/AlOx(2 nm) trilayer sputtered Si/SiO2 under oxidation annealing processes by combined x-ray reflectivity absorption studies. describe progressive inhomogeneous layers increasing time. Before annealing, have lower density than bulk samples noticeable roughness. After thermal significant improvement quality alumina layer goes along with formation CoPt alloy that reduces number Co-O bonds. These structural outcomes...
The in-depth selectivity of magneto-optical second-harmonic generation (MSHG) is investigated in the $\mathrm{CoO}∕\mathrm{Co}∕\mathrm{NiO}∕\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Ni}∕\mathrm{Cu}$ film structure. ${p}_{\text{in}}{p}_{\text{out}}$ MSHG essentially selective to only one $\mathrm{NiO}∕\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Ni}$ buried magnetic interface, whereas ${p}_{\text{in}}{s}_{\text{out}}$ and ${s}_{\text{in}}{p}_{\text{out}}$ shown be magnetically sensitive all...
Perpendicular magnetic anisotropy at metal/oxide interfaces continues to receive great interest, from the viewpoints of both fundamental research and spintronic applications. In a detailed investigation properties Pt/Co/AlO${}_{x}$ sandwiches, unusual phenomena are observed, including reorientation as function temperature, onset exchange bias associated with very large coercivity field low temperature. These interpreted in terms chemical bonding varying material phases trilayers.