A5048013896- Magnetic properties of thin films
- Advanced X-ray Imaging Techniques
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Magnetic and transport properties of perovskites and related materials
- Advanced Electron Microscopy Techniques and Applications
- Theoretical and Computational Physics
- X-ray Spectroscopy and Fluorescence Analysis
- Metallic Glasses and Amorphous Alloys
- Magnetic Properties and Applications
- Crystallography and Radiation Phenomena
- Magnetic Properties and Synthesis of Ferrites
- Atomic and Molecular Physics
- Digital Holography and Microscopy
- Superconducting Materials and Applications
- Magnetic confinement fusion research
- ZnO doping and properties
- Heusler alloys: electronic and magnetic properties
- Advancements in Semiconductor Devices and Circuit Design
- Multiferroics and related materials
- Semiconductor materials and devices
- Nuclear Physics and Applications
- Ion-surface interactions and analysis
- Force Microscopy Techniques and Applications
- Laser-Plasma Interactions and Diagnostics
Consejo Nacional de Investigaciones Científicas y Técnicas
2012-2023
Comisión Nacional de Energía Atómica
2016-2021
Synchrotron soleil
2012-2017
Centro Atómico Constituyentes
2016
Centre National de la Recherche Scientifique
2012-2015
Sorbonne Université
2012-2015
Université Paris Cité
2014-2015
Laboratoire de Chimie Physique - Matière et Rayonnement
2013-2014
Laboratoire de Chimie Physique
2012
Institut des NanoSciences de Paris
2012
The evolution of a magnetic domain structure upon excitation by an intense, femtosecond infrared (IR) laser pulse has been investigated using single-shot based time-resolved resonant x-ray scattering at the free electron LCLS. A well-ordered stripe pattern as present in thin CoPd alloy film used prototype for this study. fluence IR pump was sufficient to lead almost complete quenching magnetization within ultrafast demagnetization process taking place first few hundreds femtoseconds...
The SOLEIL synchrotron radiation source is regularly operated in special filling modes dedicated to pump–probe experiments. Among others, the low-α mode operation characterized by shorter pulse duration and represents natural bridge between 50 ps pulses femtosecond Here, capabilities of experimental set-ups developed at TEMPO beamline perform experiments with soft X-rays based on photoelectron or photon detection are presented. A 282 kHz repetition-rate laser synchronized time structure...
We present a method for imaging magnetic domains via x-ray Fourier transform holography at linearly polarized sources.Our approach is based on the separation of holographic mask and sample Faraday rotation induced reference wave.We compare images perpendicular obtained with either or circularly x-rays discuss relevance this to future experiments free-electron laser high-harmonic-generation sources.
Integration of Spin Torque Nano-Oscillators STNO's in conventional microwave circuits means that the devices have to meet certain specifications. One most important criteria is phase noise, being key parameter evaluate performance and define possible applications. Phase locking several oscillators together has been suggested as a decrease noise consequently, linewidth. In this work we present experiments, numerical simulations an analytic model describe effects thermal injection tunnel...
We present an experimental and theoretical study of the anomalous Hall effect (AHE) in MnAs epilayers grown over GaAs, with aim to identify intrinsic contribution AHE, which can be accurately evaluated using ab initio electronic structure calculations. Our magnetotransport measurements show a quadratic behavior resistivity longitudinal resistivity, characteristic scattering-independent processes, thus enabling comparison our The calculated Berry phase AHE is quantitative agreement measured...
Field-induced domain wall (DW) dynamics was investigated in MnAs/GaAs(100) films by means of longitudinal Kerr microscopy and a field pulse technique. Saw-tooth type domains were observed the studied temperature range. DW velocities up to 950 m s−1 measured at 200 K 540 290 K, beginning nucleation non-ferromagnetic β phase within ferromagnetic α phase. Different propagation regimes depending on magnitude Walker compared depinning field, which depends progressive an unordered The results are...
Size and orientation effects on the phase coexistence in MnAs/GaAs(001) microribbons were studied using magnetic force microscopy. The magnetostructural reported MnAs thin films is also observed microribbons, even smallest ones. However, stripe array of only preserved ribbons confined along [0001] direction. Nevertheless, configuration magnetoelastic domains altered $[11\overline{2}0]$ In this last case, micrometric exhibit a redistribution phases owed to relaxation epitaxial strains....
The most advanced X-ray sources (third generation synchrotrons, linear free-electron lasers and high-harmonic sources) widen the range of application scattering techniques considerably. Beyond flux brilliance, improvements in polarization tuneability, degree coherence selectable time-structure promoted new methods for investigating electronic magnetic properties solids. soft (50-2000 eV) is well suited studying magneto-optical effects laterally confined submicron sized objects, either...
We present recent developments of our table-top femtosecond high flux harmonic beamline towards single-shot probing magnetic nanostructures. High generation (HHG) optimization in a single and two-color infrared laser pulse mode was investigated at energy. Up to 109 photons per are generated between 40 80 eV shot. These soft X-ray employed characterize the nanoscale network Co/Pd multilayer samples using resonant small-angle scattering. Selecting harmonics vicinity magnetically dichroic...
The micromagnetic domain structure of MnAs films gave place to an intense research activity in the last few years due its potential application magneto-electronic devices such as domain-wall track memories and logic circuits. These applications require a full knowledge miniaturization effects on magnetic properties material. In this work, X-ray photoemission electron microscopy has been used for imaging domains lithographically fabricated ribbons, addressing dependence configuration film...
We present an experimental study of the magnetoelectric coupling (MEC) in Fe-Ga/PMN-PT thin film multiferroic composite by means x-ray magnetic circular dichroism (XMCD) and ferromagnetic resonance (FMR). Our measurements show evidence for a charge mediated mechanism, suggested asymmetric remanence (M$_{rem}$) behaviour under opposite electric fields ($\pm$ E) field (H$_r$) FMR measurements. Also, reveal perpendicular anisotropy (PMA), that can be related to interface effect. it is tunable E...
Size effects and their consequences in the thermal stability of magnetization micro-sized MnAs/GaAs(100) ribbons were studied by magnetic force microscopy. We found out that orientation which size is reduced plays a key role configuration patterns. On one hand, when reducing [0001] α-MnAs direction, system shows an improvement remanent magnetization. other [11-20] goes through reconfiguration from in-plane magnetized to out-of-plane magnetized, also improves stability.
Understanding ultrafast dynamics of nanoscale objects is an important challenge in nanoscience and technology. Their investigation relies on the availability probe techniques capable combining femtosecond time resolution with nanometer spatial resolution. Such experiments benefit greatly from recent advent x-ray free electron laser facilities. The extreme intensity their short pulses enables snapshot characterization Here, we demonstrate that such are not uniquely limited to large-scale...
We analyze the influence of Fermi surface (FS) shape on magnetotransport properties, particularly Hall effect in MnAs compound. Evidence opposite conduction polarities for different crystal directions (goniopolarity) and a strong dependence carrier type has been observed films with an applied magnetic field. To understand this behavior, we developed semiclassical model together Boltzmann transport theory that takes into account both field FS shape. The is obtained by means density functional...
We have synthesized and study the magnetic properties of (Fe0.25Nd0.75)0.6B0.4 amorphous nanoparticles. These particles were prepared in dispersed (polymeric matrix) powder systems order to investigate both internal effects arising from interactions among them. The results obtained for evidence presence an structure with a magnetically ordered core plus paramagnetic shell. At low temperature, moment interacts shell (intraparticle interaction) inducing enhancement effective anisotropy...
We performed x-ray holography experiments using synchrotron radiation. By analyzing the scattering of coherent circularly polarized x-rays tuned at Co-2p resonance, we imaged perpendicular magnetic domains in a Co/Pd multilayer. compare results obtained for continuous and laterally confined films.
Experiments, numerical simulations and an analytic model were developed to elucidate the effects of noise in synchronized state a tunnel junction based spin torque nano oscillator (STNO). It is demonstrated that plane magnetized structure, while frequency locked, much higher reference currents are needed reduce by phase locking. Our analysis shows it possible control microwave current (IRF) can be further reduced increasing bias (IDC) oscillator, keeping feasible limits for applications.
We analyze the influence of Fermi surface (FS) shape on magnetotransport properties, particularly Hall effect in MnAs compound. It has been observed films evidence opposite conduction polarities for different crystal direction (goniopolarity) and a strong dependence carrier type with applied magnetic field. In order to understand this behaviour, we developed model based semiclassical equations along Boltzmann transport theory that takes into account both, field FS shape. The compound is...