A5040152141- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Multiferroics and related materials
- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Rare-earth and actinide compounds
- Theoretical and Computational Physics
- Electronic and Structural Properties of Oxides
- X-ray Diffraction in Crystallography
- High-pressure geophysics and materials
- Advanced X-ray Imaging Techniques
- Characterization and Applications of Magnetic Nanoparticles
- Magnetic Properties and Synthesis of Ferrites
- Ferroelectric and Piezoelectric Materials
- Magnetic Properties of Alloys
- Atomic and Subatomic Physics Research
- Iron-based superconductors research
- Nuclear Physics and Applications
- Geophysical and Geoelectrical Methods
- Crystallography and Radiation Phenomena
- Inorganic Fluorides and Related Compounds
- Magneto-Optical Properties and Applications
- Advanced Electron Microscopy Techniques and Applications
- Quantum, superfluid, helium dynamics
- Photorefractive and Nonlinear Optics
Paul Scherrer Institute
2016-2025
ETH Zurich
2016-2025
Phoenix Scientific Industries (United Kingdom)
2019-2024
Swiss Federal Laboratories for Materials Science and Technology
2022
University of Basel
2022
University of Cambridge
2022
Max Planck Institute for Chemical Physics of Solids
2022
Swiss Light Source
2006-2018
Kyoto University
2018
Japan Synchrotron Radiation Research Institute
2018
Multiferroics have attracted strong interest for potential applications where electric fields control magnetic order. The ultimate speed of via magnetoelectric coupling, however, remains largely unexplored. Here, we report an experiment in which drove spin dynamics multiferroic TbMnO3 with intense few-cycle terahertz (THz) light pulse tuned to resonance electromagnon, electric-dipole active excitation. We observed the resulting motion using time-resolved resonant soft x-ray diffraction. Our...
Resonant x-ray scattering is used to detect microscopic loop currents within the plane of cupric oxide.
We report on the ultrafast dynamics of magnetic order in a single crystal CuO at temperature 207 K response to strong optical excitation using femtosecond resonant x-ray diffraction. In experiment, laser pulse induces sudden, nonequilibrium increase disorder. After short delay ranging from 400 fs 2 ps, we observe changes relative intensity ordering diffraction peaks that indicate shift collinear commensurate phase spiral incommensurate phase. These results ultimate speed for this...
Soft x-ray resonant scattering at the Ni ${L}_{2,3}$ edges is used to test models of magnetic- and orbital-ordering below metal-insulator transition in ${\mathrm{NdNiO}}_{3}$. The large branching ratio ${L}_{3}$ ${L}_{2}$ intensities $(1∕2\phantom{\rule{0.3em}{0ex}}0\phantom{\rule{0.3em}{0ex}}1∕2)$ reflection observed azimuthal angle polarization dependence originates from a noncollinear magnetic structure. absence an orbital signal structure show that nickelates are materials for which...
Up to now the crystallographic structure of magnetoelectric perovskite EuTiO3 was considered remain cubic down low temperature. Here we present high resolution synchrotron X-ray powder diffraction data showing existence a structural phase transition, from Pm-3m tetragonal I4/mcm, involving TiO6 octahedra tilting, in analogy case SrTiO3. The temperature evolution tilting angle indicates second-order transition with an estimated Tc=235K. This critical is well below recent anomaly reported by...
Recent advances in fabrication techniques to create mesoscopic 3D structures have led significant developments a variety of fields including biology, photonics, and magnetism. Further progress these areas benefits from their full quantitative structural characterization. We present resonant ptychographic tomography, combining hard x-ray phase imaging elastic scattering achieve ab initio element-specific characterization cobalt-coated artificial buckyball polymer scaffold at the nanoscale. By...
Soft x-ray resonant magnetic diffraction at the Nd $M$ edges was performed on a $\mathrm{Nd}\mathrm{Ni}{\mathrm{O}}_{3}$ epitaxial film to investigate ordering of ions below metal-insulator transition. A noncollinear structure induced by Ni moments best describes azimuthal angle dependency $(1∕2,0,1∕2)$ reflection. This confirms spin observed with soft experiments $L$ edge, providing further evidence charge disproportionation without orbital order transition in...
We investigated the magnetic structure of an orthorhombic YMnO(3) thin film by resonant soft x-ray and hard diffraction. observed a temperature-dependent incommensurate reflection below 45 K commensurate lattice-distortion 35 K. These results demonstrate that ground state is composed coexisting E-type cycloidal states. Their different ordering temperatures clarify origin large polarization to be caused antiferromagnetic states in film.
Using ultrafast resonant soft x-ray diffraction, we demonstrate photoinduced melting of antiferromagnetic order in the correlated electron insulator NdNiO${}_{3}$. Time-dependent analysis diffraction spectra allows us to follow temporal evolution charge imbalance between adjacent Ni sites. A direct correlation magnetic and rebalancing is found. Furthermore, that ordering on Nd sites, which are locked together equilibrium, become decoupled during this nonthermal process.
Using x-ray magnetic nanotomography the internal magnetization structure within extended samples can be determined with high spatial resolution and element specificity, without need for assumptions or prior knowledge of properties a sample. Here we present details new algorithm reconstruction three-dimensional vector field, discussing both mathematical description problem, gradient-based iterative routine. To test accuracy method is demonstrated complex simulated configuration obtained from...
Critical behavior is very common in many fields of science and a wide variety many-body systems exhibit emergent critical phenomena. The beauty phase transitions lies their scale-free properties, such that the temperature dependence physical parameters differing at microscopic scale can be described by same generic power laws. In this work we establish properties antiferromagnetic transition artificial square ice, showing it belongs to two-dimensional Ising universality class, which extends...
The relationship between magnetization and light has been the subject of intensive research for past century. Herein, impact on polarization is well understood. Conversely, manipulation magnetism with polarized being investigated to achieve all‐optical control magnetism, driven by potential technological implementation in spintronics. Remarkable discoveries, such as single‐pulse switching thin films submicrometer structures, have reported. However, demonstration local optical at nanoscale...
An experimental approach to the analysis of charge, magnetic and orbital ordering in 3d transition-metal oxides is presented. The technique combines two important components: azimuthal rotations around Bragg wavevector polarization intensities range 500-900 eV. performed using graded multilayers, which are translated rotated vacuum chamber. It shown why these components determine origin scattered signals how they allow us separate different contributions. Examples given for oxygen K Mn, Co,...
Magnetic resonant x-ray scattering experiments have been performed on a single crystal of ${\text{EuFe}}_{2}{\text{As}}_{2}$ at the $\text{Eu}\text{ }{L}_{3}$ absorption edge. The orientation Eu magnetic moments was directly determined: in antiferromagnetic (AFM) ordered phase they lay parallel to crystallographic $a$ axis. In addition, nonresonant measurements indicate that Fe are aligned along same direction spin-density-wave phase. As deduced by temperature dependence integrated...
We combine neutron powder diffraction and x-ray single-crystal magnetic at the Eu $L$${}_{2}$ edge to scrutinize motif of ions in magnetoelectric EuTiO${}_{3}$. Our measurements are consistent with an antiferromagnetic $G$-type pattern moments ordering along $a,b\phantom{\rule{0.16em}{0ex}}$-plane diagonal. Recent reports a novel transition 2.75 K flop upon poling sample electric field cannot be confirmed for nonpoled sample. data do not show any significant change structure below N\'eel...
The control of the electron spin by external means is a key issue for spintronic devices. Using spin- and angle-resolved photoemission spectroscopy (SARPES) with three-dimensional detection, we demonstrate operando electrostatic manipulation in ferroelectric GeTe multiferroic Ge1-xMnxTe. We not only first time Rashba semiconductors due to polarization reversal, but are also able follow switching pathway detail, show gain Rashba-splitting strength under fields. In Ge1-xMnxTe SARPES reveals...
Two-dimensional magnetic systems with continuous spin degrees of freedom exhibit a rich spectrum thermal behaviour due to the strong competition between fluctuations and correlations. When such incorporate coupling via anisotropic dipolar interaction, discrete symmetry emerges, which can be spontaneously broken leading low-temperature ordered phase. However, experimental realisation two-dimensional in crystalline materials is difficult since usually much weaker than exchange interaction....
The study of magnetic correlations in dipolar-coupled nanomagnet systems with synchrotron x-ray scattering provides a means to uncover emergent phenomena and exotic phases, particular thermally active moments. From the diffuse signal soft resonant scattering, we have measured highly dynamic artificial kagome spin ice sub-70-nm Permalloy nanomagnets. On comparing experimental patterns Monte Carlo simulations based on needle-dipole model, conclude that I phase exist our system even presence...
The single photon counting microstrip detector MYTHEN III was developed at the Paul Scherrer Institute to satisfy increasing demands in performance of synchrotron radiation experiments, focusing on time-resolved and on-edge powder diffraction measurements. Similar II, installed Material Science beamline covers 120° 2θ. It is based III.0 readout chip wire-bonded silicon strip sensors with a pitch 50 µm, it provides improved features respect previous version. Taking advantage three independent...
Transition metal oxides, with their wide range of electronic and magnetic properties, offer a remarkable platform for developing future electronics based on unconventional quantum phenomena, such as topological phases. The formation topologically nontrivial states is linked to crystalline symmetry, spin-orbit coupling, ordering. Here, by employing angle-resolved photoemission spectroscopy (ARPES), supported density functional theory (DFT) calculations, we demonstrated that intrinsic...
Detailed resonant x-ray diffraction experiments including azimuthal angle scans were performed on $\mathrm{Nd}\mathrm{Ni}{\mathrm{O}}_{3}$ around the Ni $K$ absorption edge, allowing us to investigate electronic changes associated with metal-to-insulator transition. The influence observed reflections of charge disproportionation and asphericity electron density is evaluated. asphericity, due distortion oxygen octahedra, persists also in metallic phase, but its unrotated...
We present a theoretical analysis of resonant x-ray Bragg diffraction data from multiferroic ${\text{TbMnO}}_{3}$ presented by Mannix et al. [Phys. Rev. B 76, 184420 (2007)] and Voigt 104431 (2007)]. have chosen an approach that does not rely on knowledge the low-temperature phase space group sample, which is precisely known. Results show satellite reflections originate dipole-dipole (E1-E1) dipole-quadrupole (E1-E2) events. Presence quadrupole-quadrupole (E2-E2) events can be excluded. The...