Spin Waves Excited by Hard X-Ray Transient Gratings

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Electron magnetic circular dichroism (EMCD) in transmission electron microscopy (TEM) enables element-specific measurement of spin and orbital magnetic moments, analogous to x-ray magnetic circular dichroism (XMCD). While the EMCD technique offers unmatched spatial resolution, its quantitative accuracy remains under scrutiny, particularly in beam-splitter geometries with convergent probes. Here, we systematically evaluate the limits of quantitative EMCD analysis using the first-order magnetostructural trans

This document corresponds to the current pre-final version of a doctoral thesis on continuous-wave nonlinear mid-infrared vibrational spectroscopy in dual-resonant plasmonic nanocavities. Conventional vibrational sum- and difference-frequency generation (SFG/DFG) provide interface-specific chemical fingerprints, but in practice their spectral access, stability, and reproducibility remain closely tied to ultrafast sources, synchronization, and phase-matching pipelines. This thesis addresses that constraint b

Overhauser-effect dynamic nuclear polarization (OE-DNP) is an emerging method for enhancing the sensitivity of high-resolution nuclear magnetic resonance (NMR) in liquids. OE-DNP generates nuclear spin hyperpolarization by electron-to-nuclear cross-relaxation between the analyte and a paramagnetic polarizing agent doped into the NMR solution. The key advantage of this method is the in situ enhancement of nuclear polarization under steady-state, which is inherently compatible with multiscan signal averaging

Plasma state reconstruction methods combining measurements and physics modeling improve the estimation of physics quantities in real-time and in post-discharge analysis. We present a workflow to reconstruct the dynamic evolution of a set of internal tokamak plasma profiles with consistent equilibria, as applied in this paper for experimental data from TCV L and H-mode discharges. Plasma profile estimates for electron temperature Te, electron density ne and parallel current density jpar are obtained by data

We report microwave spectroscopy of 167Er3+ doped in CaWO4, which reveals the hyperfine splitting of the erbium electronic ground state (Z1, Jeff = 15/2) induced by the I = 7/2 nuclear spin. From spectra measured below similar to 50 mK in magnetic fields up to 200 mT, we extract spin-Hamiltonian parameters including the electron g, hyperfine A, and nuclear electric quadrupolar Q tensors. Crucially, our analysis demonstrates unambiguously that the previously unobserved nuclear electric quadrupolar moment is

PKS 2155-304 is a well-known high-frequency peaked BL Lac (HBL) at redshift z=0.116, which has been extensively studied across the electromagnetic spectrum due to its rapid and large-amplitude variability. Several violent outbursts in X-rays and γ-rays have been observed in the past, with intra-night variability in very-high-energy γ-rays (VHE; E > 100 GeV) detected down to the minute timescale. The alternation of quiescent and enhanced states, observed with a tentative quasi-periodicity of 1.74 ± 0.13 year

Time reversal is an established wave imaging and focusing method that has proved to be robust and compatible with super-resolution imaging and focusing, i.e., to provide images and foci with subwavelength features beyond the diffraction limit. The method has been applied to numerous wave systems. We propose a systematic review of super-resolution time reversal applied to electromagnetic waves in the radio-frequency regime. We examine the theoretical foundation, the methods and the applications of radio-freq

Context. The magnetic field has been shown to play a crucial role in star formation. Dust polarization is one of the most effective tools for probing the properties of the magnetic field, yet it does not directly trace its strength. To bridge this gap, several methods have been developed, combining polarization and spectroscopic data, to estimate the strength of the magnetic field. The most widely applied method was developed by Davis (1951, Phys. Rev., 81, 890) and Chandrasekhar & Fermi (1953, ApJ, 118, 11

The catastrophic tsunami events in 2004 and 2011 revealed that buildings with large openings often resisted better to the hydrodynamic impact of the wave. The steel or concrete structure of the building remained intact and the upper floors could serve as shelters. Dr. Davide Wüthrich conducted a comprehensive and systematic experimental benchmark study in order to identify the effect of building openings on the hydrodynamic loadings during wave impact. A sophisticated experimental set-up was developed, whic

We investigated the magnetic properties of individual Ho atoms adsorbed on the (111) surface of Pt, which have been recently claimed to display single ion magnetic behavior. By combining x-ray absorption spectroscopy and magnetic dichroism measurements with ligand field multiplet calculations, we reveal a ground state which is incompatible with long spin relaxation times, in disagreement with former findings. A comparative study of the ground state and magnetic anisotropy of Ho and Er on Pt(111) and Cu(111)

The paper reports on a graphical user interface developed in MATLAB to aid the visualization of the plane wave impinging from a lossless half-space onto a multilayer structure. Individual layers are assumed to be homogeneous and isotropic with electric permittivity (∊) and magnetic permeability (μ) taking arbitrary complex values. Double-positive, single-negative and double-negative media (real parts of ∊ and μ) as well as lossless, dissipative and amplifying media (imaginary parts of ∊ and μ) are allowed.

Photon counting is useful in space-based imagers wherever quantitative light- intensity evaluation is necessary. Various types of radiation, from cosmic rays to high-energy proton beams to gamma radiation, have an effect on the functionality and accuracy of imagers and the literature is extensive. Techniques to maximize sensor tolerance have also been developed for a number of years and several imagers resistant to up to 30Mrad (Si) of gamma radiation have been reported. These sensors have several shortcomi

Sample prepn. and ligand complex prepn. of Hb I from Lucina pectinata were performed to obtain ultrafast data on ferric HbI-NO, HbI-N3, HbI-H2S and metHbI complexes that suggest a mechanism for the photoinduced redn. of HbI species. Formation of a transient species in the 430 nm region of the ferric derivs., plus the fact that subsequent to the ultrafast measurements a ferrous oxy HbI species was obsd., led to the suggestion that probably a redn. of a ferric to a ferrous deriv. was occurring. Hb I photoredn

We have observed marked oscillations in the time-resolved photoluminescence of a semiconductor microcavity under non-resonant excitation conditions. Hot excitons, created with an ultrashort light pulse, rapidly relax into polaritons in the cavity with a large in-plane momentum K. Shortly after illumination, above a certain excitation power, the polaritons accumulate into an energy trap at the bottom of the dispersion and the light emission, governed by final-state stimulated scattering, starts at K similar

Light Induced Chemical Vapour Deposition (LICVD) of titanium dioxide thin films is studied in this work. It is shown that this technique enables to deposit locally and selectively a chosen crystalline phase with a precise controlled thickness at low substrate temperature, allowing even the use of polymer substrates. A home made LICVD reactor was set up, consisting of a main chamber in which the substrate was placed on a temperature controlled plate and could be irradiated perpendicularly through a window by

The analysis and interpretation of perturbative modulated electron cyclotron heating (MECH) discharges for power deposition localization using different diagnostics, such as electron cyclotron emission (ECE) and soft x-ray (SXR) measurements, are presented. In particular, the experimental determination of the MECH power deposition is investigated, which is a fundamental requirement, for example, for heat transport studies. The most important problem is related to the coupling between the MECH and the sawtoo

We construct atomistic models of the Si(100)-SiO2 interface in accord with available experimental data. Combining classical and first-principles simulation methods, we generate transition structures from crystalline silicon to disordered SiO2. The generation procedure accounts for the density of coordination defects, the amount and location of partially oxidized Si atoms, and the mass density profile, as measured in electron-spin-resonance, photoemission, and x-ray reflectivity experiments, respectively. A

Spectroscopic measurements on ethylene were performed using a quasi-room-temperature quantum cascade (QC) laser operated in pulsed mode in the 10.3 μm range. Using transmission spectroscopy, a broadening of the ethylene absorption spectrum was observed with increasing laser pulse duration, due to an increase of the laser linewidth. This linewidth was determined from the measured absorption spectra, showing a value of 0.04 cm-1 for a 20 ns pulse duration and an enhancement coefficient of 6.5 × 10-3 cm -1 per

Properties of ultra-thin films are different from their single crystal counterparts due to the presence of (substrate induced) strain, different degree and type of (growth induced) disorder and different average doping (distribution of oxygen vacancies, for example). Here we briefly summarize main results on ultra-thin (99 --> 1 unit cell (UC)) superconducting oxide films grown by laser ablation. Systematic studies show that BSCCO-2212, 2201, 2223, and LSCO-214 exhibit conductor-like Fermi edge, whereas mat

In typical power applications, Bi-2223 conductors carrying ac current will be subjected to external magnetic fields, whose orientation and conductor’s geometry are of major significance for the ac loss magnitude. This paper investigates the influence of the geometry and aspect ratio of non-twisted Bi-2223 conductors in reducing the ac loss for such applications. A numerical model of high-Tc materials has been used in finite-element-method simulations. The model incorporates power-law E-J characteristics wit

Spin Waves Excited by Hard X-Ray Transient Gratings

Chat with Graph Search

Sub-10-nm quantification of spin and orbital magnetic moment across the metamagnetic phase transition in FeRh using EMCD

A Co-programmable Platform for Continuous-Wave Ultra-Broadband Nonlinear Mid-IR Vibrational Spectroscopy

Recent progress in high-field liquid-state Overhauser dynamic nuclear polarization

Model-based Estimation of Tokamak Plasma Profiles and Physics Parameters: Integration with Improved Equilibrium Reconstruction and Experimental Data

Nuclear quadrupole interaction and zero first-order Zeeman transitions of 167Er3+in CaWO4

Recent observations of PKS 2155-304 with MAGIC and LST-1 in a multi-wavelength context

Radio-frequency Subwavelength Time-reversal Imaging and Focusing: A Review of Theory, Methods, and Applications

A three-step approach to reliably estimate magnetic field strengths in star-forming regions

Extreme Hydrodynamic impact onto buildings

Magnetism of Ho and Er Atoms on Close-Packed Metal Surfaces

A MATLAB-based tool for visualizing the plane wave propagation in multilayer structures containing metamaterials

A gamma, x-ray and high energy proton radiation-tolerant CIS for space applications

Ultrafast studies of ferric complexes of hemoglobin I from Lucina pectinata

Oscillatory behaviour in the nonlinear emission of semiconductor microcavities

Selective light induced chemical vapour deposition of titanium dioxide thin films

Signal processing techniques based on singular value decomposition applied to modulated ECH experiments

Atomistic structure of the Si(100)-SiO2 interface: A synthesis of experimental data

Ethylene spectroscopy using a quasi-room-temperature quantum cascade laser

Systematic studies of (magneto)transport, structural and electronic properties of ultra-thin films of high-T-c cuprates and related layered oxides

Geometry considerations for use of Bi-2223/Ag tapes and wires with different models of Jc(B)