A5085216636- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Magnetic Properties and Applications
- Theoretical and Computational Physics
- Magneto-Optical Properties and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Magnetic and transport properties of perovskites and related materials
- ZnO doping and properties
- Advanced Condensed Matter Physics
- Magnetic Properties of Alloys
- Advanced Memory and Neural Computing
- Electronic and Structural Properties of Oxides
- Advanced Electron Microscopy Techniques and Applications
- Surface and Thin Film Phenomena
- Semiconductor Quantum Structures and Devices
- Topological Materials and Phenomena
- Multiferroics and related materials
- Magnetic Field Sensors Techniques
- Atomic and Subatomic Physics Research
- Neural Networks and Reservoir Computing
- Corporate Governance and Management
- Heusler alloys: electronic and magnetic properties
- Thermal properties of materials
- Geomagnetism and Paleomagnetism Studies
Technical University of Munich
2018-2025
Munich Center for Quantum Science and Technology
2019-2025
University of Regensburg
2013-2023
Istituto Nazionale di Ricerca Metrologica
2023
Max Planck Institute for Intelligent Systems
2016-2021
Beihang University
2020
University of California, Los Angeles
2020
Hefei Institute of Technology Innovation
2020
Nanosystems Initiative Munich
2019
Ludwig-Maximilians-Universität München
2017
In solid-state materials with strong relativistic spin-orbit coupling, charge currents generate transverse spin currents. The associated Hall and inverse effects distinguish between current where electron is a conserved quantity but its direction not. This review provides theoretical experimental treatment of this subfield spintronics, beginning distinct microscopic mechanisms seen in ferromagnets concluding discussion optical-, transport-, magnetization-dynamics-based experiments closely...
Magnonics addresses the physical properties of spin waves and utilizes them for data processing. Scalability down to atomic dimensions, operation in GHz-to-THz frequency range, utilization nonlinear nonreciprocal phenomena, compatibility with CMOS are just a few many advantages offered by magnons. Although magnonics is still primarily positioned academic domain, scientific technological challenges field being extensively investigated, proof-of-concept prototypes have already been realized...
The notion of non-trivial topological winding in condensed matter systems represents a major area present-day theoretical and experimental research. Magnetic materials offer versatile platform that is particularly amenable for the exploration spin solitons real space such as skyrmions. First identified non-centrosymmetric bulk materials, rapidly growing zoology hosting skyrmions related includes compounds, surfaces, thin films, heterostructures, nano-wires nano-dots. This underscores an...
Micron-sized magnetic platelets in the flux-closed vortex state are characterized by an in-plane curling magnetization and a nanometer-sized perpendicularly magnetized core. Having simplest non-trivial configuration, these objects of general interest to micromagnetics may offer new routes for spintronics applications. Essential progress understanding nonlinear dynamics was achieved when low-field core toggling excitation gyrotropic eigenmode at sub-GHz frequencies established. At more than...
In magnetically ordered systems the Heisenberg exchange interaction between neighboring spins favors collinear alignment such as that seen in ferromagnets and antiferromagnets. The inclusion of antisymmetric exchange, also known Dzyaloshinskii--Moriya (DMI), promotes an orthogonal arrangement is subject this review. DMI responsible for chiral magnetism, spin-textured skyrmions, magnetoelectric effects multiferroic materials. review, organized by measurement method, focused on experiments...
Abstract Reservoir computing is a neuromorphic architecture that may offer viable solutions to the growing energy costs of machine learning. In software-based learning, performance can be readily reconfigured suit different computational tasks by tuning hyperparameters. This critical functionality missing in ‘physical’ reservoir schemes exploit nonlinear and history-dependent responses physical systems for data processing. Here we overcome this issue with ‘task-adaptive’ approach computing....
Ultrafast magnetic field pulses as short 2 picoseconds are able to reverse the magnetization in thin, in-plane, magnetized cobalt films. The applied plane of film, and their direction encompasses all angles with magnetization. At a right angle magnetization, maximum torque is exerted on spins. In this geometry, precessional reversal can be triggered by fields small 184 kiloamperes per meter. Applications future ultrafast recording schemes foreseen.
We report on imaging of three-dimensional precessional orbits the magnetization vector in a magnetic field by means time-resolved vectorial Kerr experiment that measures all three components with picosecond resolution. Images mode taken submicrometer spatial resolution reveal dynamical excitation this time regime roughly mirrors symmetry underlying equilibrium spin configuration and its propagation has non-wavelike character. These results should form basis for realistic models dynamics...
Thin-circular lithographically defined magnetic elements with a spin vortex configuration are excited short perpendicular field pulse. We report the first images of eigenmodes up to third order, obtained by means phase sensitive Fourier transform imaging technique. Both axially symmetric and symmetry breaking azimuthal observed. observe strong oscillations magnetization in central part elements. The experimental data good agreement micromagnetic simulations.
Strong in-plane magnetic field pulses of 2--4.4 ps duration are used to study magnetization reversal in perpendicularly magnetized Co/Pt films. Ring domains, reminiscent the contour during exposure, observed later with Kerr microscopy. Their radii represent switching fields which quantitative agreement coherent rotation model. The observation intrinsic transition broadening is attributed existence static and dynamic fluctuations anisotropy.
We report on the observation of magnetic vortex dynamics in response to rotating fields submicron platelets. Unlike linear or spin polarized currents, which excite both core polarization states, an in-plane field can selectively one states. demonstrate by direct imaging with time-resolved scanning x-ray microscopy that only excites gyrotropic mode if rotation sense coincides gyration and such a reverse polarization.
We report the main characteristics of advanced photoelectric effect experiments beamline, operational at Elettra storage ring, featuring a fully independent double branch scheme obtained by use chicane undulators and able to keep polarization control in both linear circular mode. The paper describes novel technical solutions adopted, namely, (a) design quasiperiodic undulator resulting optimized suppression higher harmonics over large photon energy range (10-100 eV), (b) thermal stability...
Transverse magneto-thermoelectric effects are studied in permalloy thin films grown on MgO and GaAs substrates compared to those suspended SiN membranes. The transverse voltage along platinum strips patterned top of the is measured vs. external magnetic field as a function angle temperature gradient. After identification contribution planar anomalous Nernst effects, we find an upper limit for spin Seebeck effect, which several orders magnitude smaller than previously reported.
Spin pumping in ferromagnets provides a source of pure spin currents. Via the inverse Hall effect current is converted into charge and corresponding detectable DC-voltage. The ratio injected to resulting given by angle. However, number experiments more or less equals different values for angles, even most studied normal metal platinum. This publication full study anisotropic magnetoresistance NiFe(Py) / bilayers using coplanar waveguide structure. Angle frequency dependent measurements...
Doping ${\mathrm{Ni}}_{80}{\mathrm{Fe}}_{20}$ by heavy rare earth atoms alters the magnetic relaxation properties of this material drastically. We show that effect can be well explained slow relaxing impurity mechanism. This process is a consequence anisotropy on site exchange interaction between $4f$ moments and conduction band. As expected from model magnitude damping scales with increases an order at low temperatures. In addition, our measurements allow us to determine time electrons as...
Entropic effects counteract the topological protection of magnetic skyrmions, leading to faster decay rates than expected.
All-electrical spin-wave spectroscopy, Brillouin light scattering, as well the magneto-optical Kerr effect are combined to study propagation through a magnetic antidot lattice nanopatterned into Ni(80)Fe(20) thin film. The velocities and, in particular, relaxation found depend characteristically on applied in-plane field. We explain observed anisotropies by field-controlled guiding network of interconnected nanowires which takes place over distances up 20 μm.
Abstract In spin electronics, the degree of freedom is used to transmit and store information. To this end ability create pure currents—that is, without net charge transfer—is essential. When magnetization vector in a ferromagnet–normal metal junction excited, pumping effect leads injection currents into normal metal. The polarization current time-dependent contains very small d.c. component. Here we show that large a.c. component can be detected efficiently using inverse Hall effect....
We use time-resolved x-ray diffraction and magnetic optical Kerr effect to study the laser induced antiferromagnetic ferromagnetic phase transition in FeRh. The structural response is given by nucleation of independent domains (\tau_1 ~ 30ps). This significantly faster than (\tau_2 60ps) subsequent domain realignment. X-ray shows that two phases co-exist on short time-scales limited speed sound. A model describing both dynamics presented.
Within a combined experimental and theoretical study it is shown that the spin Hall angle of substitutional alloy system can be continuously varied via its composition. For Au_{x}Pt_{1-x} substantial increase maximum compared to pure partners could achieved this way. The findings for longitudinal charge conductivity σ, transverse σ_{SH}, α_{SH} confirmed by calculations based on Kubo's linear response formalism. Calculations these quantities different temperatures show divergent behavior σ...
We report the experimental observation of Snell's law for magnetostatic spin waves in thin ferromagnetic Permalloy films by imaging incident, refracted, and reflected waves. use a thickness step as interface between two media with different dispersion relations. Since relation is anisotropic, deviations from isotropic known optics are observed incidence angles larger than 25° respect to normal magnetic media. Furthermore, we can show that modifies wavelength amplitude incident Our findings...