A5083649336- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- ZnO doping and properties
- Material Dynamics and Properties
- Enzyme Structure and Function
- Topological Materials and Phenomena
- Multiferroics and related materials
- Graphene research and applications
- Quantum and electron transport phenomena
- Magneto-Optical Properties and Applications
- Phase Equilibria and Thermodynamics
- nanoparticles nucleation surface interactions
- Magnetic and transport properties of perovskites and related materials
- Advanced Electron Microscopy Techniques and Applications
- Shape Memory Alloy Transformations
- Magnetic Properties and Applications
- Protein Structure and Dynamics
- Advanced Condensed Matter Physics
- 2D Materials and Applications
- Neural Networks and Applications
- Metal and Thin Film Mechanics
- Heusler alloys: electronic and magnetic properties
- Advanced X-ray Imaging Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced NMR Techniques and Applications
Stockholm University
2022-2025
AlbaNova
2022-2024
Johannes Gutenberg University Mainz
2016-2023
University of Applied Sciences Mainz
2018-2023
St Petersburg University
2014-2017
We probe the current-induced magnetic switching of insulating antiferromagnet/heavy metals systems, by electrical spin Hall magnetoresistance measurements and direct imaging, identifying a reversal occurring domain wall (DW) motion. observe more than one third antiferromagnetic domains application current pulses. Our data reveal two different mechanisms leading together to an efficient switching, namely spin-current induced effective anisotropy variation action torque on DWs.
Electrical readout of the orientation an antiferromagnet by detecting N\'eel vector is necessary to exploit this class materials for applications. Here, authors study bilayers thin films epitaxial antiferromagnetic insulator NiO(001) and heavy metal Pt. The observed three-dimensional angular dependence spin Hall magnetoresistance (SMR) analyzed, considering reversible field-induced redistribution magnetostrictive $S$ $T$ domains in NiO(001). find that a careful subtraction ordinary...
In the field of antiferromagnetic (AFM) spintronics, information about N\'eel vector, AFM domain sizes, and spin-flop fields is a prerequisite for device applications but not available easily. We have investigated domains spin-flop-induced changes patterns in ${\mathrm{Mn}}_{2}\mathrm{Au}$(001) epitaxial thin films by x-ray magnetic linear dichroism photoemission electron microscopy (PEEM) using up to 70 T. As-prepared ${\mathrm{Mn}}_{2}\mathrm{Au}$ exhibit with an average size...
The effects of current induced N\'eel spin-orbit torques on the antiferromagnetic domain structure epitaxial Mn$_2$Au thin films were investigated by X-ray magnetic linear dichroism - photoemission electron microscopy (XMLD-PEEM). We observed switching AFM domains essentially corresponding to morphological features samples. Reversible as well irreversible vector reorientation was obtained in different parts samples and up 30 % all field view 10 $\mu$m is demonstrated. Our direct...
Controlling magnetism by electric fields offers a highly attractive perspective for designing future generations of energy-efficient information technologies. Here, we demonstrate that the magnitude current-induced spin-orbit torques in thin perpendicularly magnetized CoFeB films can be tuned and even increased electric-field generated piezoelectric strain. Using theoretical calculations, uncover subtle interplay coupling, crystal symmetry, orbital polarization is at core observed strain...
X-ray free-electron lasers (XFELs) with megahertz repetition rate can provide novel insights into structural dynamics of biological macromolecule solutions. However, very high dose rates lead to beam-induced and changes due radiation damage. Here, we probe the dense antibody protein (Ig-PEG) solutions using photon correlation spectroscopy (MHz-XPCS) at European XFEL. By varying total rate, identify a regime for measuring motion proteins in their first coordination shell, quantify...
The electronic and spin structure of a graphene monolayer synthesized on Pt(111) has been investigated experimentally by angle- spin-resolved photoemission with different polarizations incident synchrotron radiation using density functional theory calculations. It is shown that despite the observed total quasifreestanding character dispersion $\ensuremath{\pi}$ state remarkable local distortions breaks in dispersions take place due to hybridization between Pt $d$ states. Corresponding...
Understanding the electrical manipulation of antiferromagnetic order is a crucial aspect to enable design devices working at THz frequencies. Focusing on collinear insulating $\mathrm{Ni}\mathrm{O}/\mathrm{Pt}$ thin films as materials platform, we identify crystallographic orientation domains that can be switched by currents and quantify N\'eel-vector direction changes. We demonstrate switching between different T current pulses, finding in these along [$\ifmmode\pm\else\textpm\fi{}5$...
Metallic antiferromagnets with broken inversion symmetry on the two sublattices, strong spin-orbit coupling and high N\'{e}el temperatures offer new opportunities for applications in spintronics. Especially Mn$_{2}$Au, temperature conductivity, is particularly interesting real-world applications. Here, manipulation of orientation staggered magnetization,\textit{\ i.e.} vector, by current pulses has been recently demonstrated, read-out limited to studies anisotropic magnetoresistance or X-ray...
The modification of the graphene spin structure is interest for novel possibilities application in spintronics. most exciting them demand not only high value spin-orbit splitting states, but non-Rashba behavior and spatial modulation interaction. In this work we study electronic on Ir(111) with intercalated Pt monolayer. interlayer does change $9.3\ifmmode\times\else\texttimes\fi{}9.3$ superlattice graphene, while Dirac cone becomes modified. It shown that Rashba $\ensuremath{\pi}$ state...
The absence of stray fields, their insensitivity to external magnetic and ultrafast dynamics make antiferromagnets promising candidates for active elements in spintronic devices. Here, we demonstrate manipulation the Néel vector metallic collinear antiferromagnet Mn2Au by combining strain femtosecond laser excitation. Applying tensile along either two in-plane easy axes locally exciting sample a train pulses, align direction controlled applied strain. dependence on fluence suggests alignment...
Hydrated proteins undergo a transition in the deeply supercooled regime, which is attributed to rapid changes hydration water and protein structural dynamics. Here, we investigate nanoscale stress–relaxation hydrated lysozyme stimulated probed by X-ray Photon Correlation Spectroscopy (XPCS). This approach allows us access dynamics regime (T = 180 K), typically not accessible through equilibrium methods. The observed dynamic response collective as system transitions from jammed granular state...
We report a combined study of imaging the antiferromagnetic (AFM) spin structure and measuring Hall magnetoresistance (SMR) in epitaxial thin films insulating non-collinear antiferromagnet SmFeO$_3$. X-ray magnetic linear dichroism photoemission electron microscopy measurements reveal that AFM spins SmFeO$_3$(110) align plane film. Angularly dependent show SmFeO$_3$/Ta bilayers exhibit positive SMR, contrast to negative SMR expected previously studied collinear AFMs. The amplitude increases...
By means of angle- and spin-resolved photoemission, we demonstrate a possibility the out-of-plane spin polarization topological surface states corresponding lifting Kramers degeneracy at Dirac point induced in magnetically-doped insulator Bi1.37V0.03Sb0.6Te2Se by circularly polarized synchrotron radiation (SR) room temperature. It has been shown that is created due to an “optically”-generated uncompensated accumulation with transferring torque diluted V 3d ions. We have found theoretically...
In this work, we first statically image the electrically controlled magnetostatic configuration of magnetic vortex states and then dynamically time-resolved core gyration tuned by electric fields. We demonstrate manipulation orbit engineering anisotropies. achieve fields in a synthetic heterostructure consisting piezoelement coupled with magnetostrictive microstructures, where anisotropy can be strain. directly show strong impact tailored on static shape state dynamic orbit. The results...
Abstract Recent experiments and theoretical studies strongly indicate that water exhibits a liquid-liquid phase transition (LLPT) in the supercooled domain. An open question is how LLPT of can affect properties aqueous solutions. Here, we study structural thermodynamic glycerol-water microdroplets at dilute conditions ( χ g = 3.2% glycerol mole fraction). The combination rapid evaporative cooling with femtosecond X-ray scattering allows us to outrun crystallization gain access deeply regime...
Here, we demonstrate an experimental proof of concept for nanofocused x-ray photon correlation spectroscopy, a technique sensitive to nanoscale fluctuations present in broad range systems. The experiment, performed at the NanoMAX beamline MAX IV, uses novel event-based detector capture nanoparticle structural dynamics with microsecond resolution. By varying nanobeam size from σ=88 nm σ=2.5μm, quantify effect nanofocus on small-angle scattering lineshape and diffusion coefficients obtained...
We report unusual magnetization switching processes and angular-dependent exchange bias effects in fully epitaxial ${\mathrm{Co}}_{3}\mathrm{FeN}$/MnN bilayers, where magnetocrystalline anisotropy coupling compete, probed by longitudinal transverse magneto-optic Kerr effect (MOKE) magnetometry. The MOKE loops show multistep jumps corresponding to the nucleation propagation of ${90}^{\ensuremath{\circ}}$ domain walls as-grown bilayers. By inducing coupling, we confirm changes process due...
Modification of graphene electronic properties via contact with atoms different kind allows for designing a number functional post-silicon devices. Specifically, 2D metallic layer formation over is promising approach to improving the graphene-based systems. In this work we analyse and spin structure synthesized on Pt(111) after sodium monolayer adsorption by means angle-resolved photoemission spectroscopy ab initio calculations. Here, show that leads shift π states towards higher binding...
The understanding of antiferromagnetic domain walls, which are the interface between domains with different N\'eel order orientations, is a crucial aspect to enable use materials as active elements in future spintronic devices. In this work, we demonstrate that NiO/Pt bilayers arbitrary-shaped structures can be generated by switching driven electrical current pulses. T domains, separated from each other wall whose spins pointing toward average direction two rather than common axis planes....
Studying protein interactions at low temperatures has important implications for optimizing cryostorage processes of biological tissue, food, and protein-based drugs. One the major issues is related to formation ice nanocrystals, which can occur even in presence cryoprotectants lead denaturation. The nanocrystals solutions poses several challenges since, contrary microscopic crystals, they be difficult resolve complicate interpretation experimental data. Here, using a combination small-...
We investigate the Dzyaloshinskii–Moriya interaction (DMI) and spin–orbit torque effects in CuIr/CoFeB/MgO heterostructures. To this end, harmonic Hall measurements current induced domain wall motion experiments are performed. The of walls at zero applied field due to demonstrates presence DMI system. determine strength be D=+5 ± 3 μJ/m2 deduce right-handed chirality showing a partial Néel type spin structure. ascertain torques, we perform second measurement quantify damping- field-like...