Georg Woltersdorf

Martin Luther University Halle-Wittenberg

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

C. H. Back

Technical University of Munich

Tobias Kampfrath

Freie Universität Berlin

Liane Brandt

Martin Luther University Halle-Wittenberg

Lukáš Nádvorník

Charles University

B. Heinrich

Simon Fraser University

Niklas Liebing

Martin Luther University Halle-Wittenberg

Gisela Schütz

Max Planck Institute for Intelligent Systems

Tom S. Seifert

Fritz Haber Institute of the Max Planck Society

Hermann Stoll

Max Planck Institute for Intelligent Systems

S. Parkin

Max Planck Institute of Microstructure Physics

Cooperative Institutions

University of Regensburg

Martin Luther University Halle-Wittenberg

Max Planck Institute of Microstructure Physics

Technical University of Munich

Max Planck Society

Johannes Gutenberg University Mainz

Max Planck Institute for Intelligent Systems

ETH Zurich

Centre National de la Recherche Scientifique

Forschungszentrum Jülich

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Plasmonic Spin-Hall Effect of propagating Surface Plasmon Polaritons in Ni80Fe20 microstructures

Zenodo (CERN European Organization for Nuclear Research) (2021)

Maximilian Paleschke Cheng‐Tien Chiang Liane Brandt Niklas Liebing Georg Woltersdorf

Dataset providing the data used for the Paper "Plasmonic Spin-Hall Effect of propagating Surface Plasmon Polaritons in Ni₈₀Fe₂₀ microstructures" already published as preprint in arxiv and to be published in NJP. The metadata.txt file serves as a README to guide through the dataset. The corresponding article can be found here: https://iopscience.iop.org/article/10.1088/1367-2630/ac1c83 The preprint is still available here: https://arxiv.org/abs/2105.12501

Localized surface plasmon

10.5281/zenodo.4899539

Cite

Citations (0)

X-ray imaging of the dynamic magnetic vortex core deformation

Nature Physics (2009)

Arne Vansteenkiste Kang Wei Chou Markus Weigand Michael Curcic Vitalij Sackmann

Micromagnetics

10.1038/nphys1231

Cite

Citations (121)

Terahertz Spin‐to‐Charge Conversion by Interfacial Skew Scattering in Metallic Bilayers

Advanced Materials (2021)

Oliver Gueckstock Lukáš Nádvorník Martin Gradhand Tom S. Seifert Genaro Bierhance

Abstract The efficient conversion of spin to charge transport and vice versa is of major relevance for the detection and generation of spin currents in spin‐based electronics. Interfaces of heterostructures are known to have a marked impact on this process. Here, terahertz (THz) emission spectroscopy is used to study ultrafast spin‐to‐charge‐current conversion (S2C) in about 50 prototypical F|N bilayers consisting of a ferromagnetic layer F (e.g., Ni 81 Fe 19 , Co, or Fe) and a nonmagnetic layer N with strong (Pt) or weak (Cu and Al) spin‐orbit coupling. Varying the structure of the F/N interface leads to a drastic change in the amplitude and even inversion of the polarity of the THz charge current. Remarkably, when N is a material with small spin Hall angle, a dominant interface contribution to the ultrafast charge current is found. Its magnitude amounts to as much as about 20% of that found in the F|Pt reference sample. Symmetry arguments and first‐principles calculations strongly suggest that the interfacial S2C arises from skew scattering of spin‐polarized electrons at interface imperfections. The results highlight the potential of skew scattering for interfacial S2C and propose a promising route to enhanced S2C by tailored interfaces at all frequencies from DC to terahertz.

10.1002/adma.202006281

Cite

Citations (63)

Magnetic vortex core reversal by excitation of spin waves

Nature Communications (2011)

Matthias Kammerer Markus Weigand Michael Curcic Matthias Noske Markus Sproll

Micron-sized magnetic platelets in the flux-closed vortex state are characterized by an in-plane curling magnetization and a nanometer-sized perpendicularly magnetized vortex core. Having the simplest non-trivial configuration, these objects are of general interest to micromagnetics and may offer new routes for spintronics applications. Essential progress in the understanding of nonlinear vortex dynamics was achieved when low-field core toggling by excitation of the gyrotropic eigenmode at sub-GHz frequencies was established. At frequencies more than an order of magnitude higher vortex state structures possess spin wave eigenmodes arising from the magneto-static interaction. Here we demonstrate experimentally that the unidirectional vortex core reversal process also occurs when such azimuthal modes are excited. These results are confirmed by micromagnetic simulations, which clearly show the selection rules for this novel reversal mechanism. Our analysis reveals that for spin-wave excitation the concept of a critical velocity as the switching condition has to be modified.

Micromagnetics

Vortex state

Spin wave

Magnetization dynamics

10.1038/ncomms1277

Cite

Citations (231)

Observation of non-linear magnetic vortex gyration by X-ray microscopy and micromagnetic simulations

arXiv (Cornell University) (2011)

Arne Vansteenkiste Ben Van de Wiele Markus Weigand Hermann Stoll Kang Wei Chou

Magnetic vortex gyration in a 500 nm wide, 50 nm thick Permalloy square platelet was investigated using time-resolved scanning transmission x-ray microscopy and micromagnetic simulations. The response of the vortex core on an in-plane oscillating magnetic field was studied as a function of the excitation frequency and amplitude. Non-linear behavior was observed in the form of a redshift of the gyrotropic resonance. I.e., when the excitation amplitude was increased, the resonance frequency was found to decrease. The nonlinearity is in agreement with extensive micromagnetic simulations. This work complements previous reports on thinner nanostructures where a frequency blueshift was observed.

Permalloy

Gyration

Micromagnetics

10.48550/arxiv.1110.0828

Cite

Citations (0)

Electric‐Field Control of Propagating Spin Waves by Ferroelectric Domain‐Wall Motion in a Multiferroic Heterostructure

Advanced Materials (2021)

Huajun Qin Rouven Dreyer Georg Woltersdorf Tomoyasu Taniyama Sebastiaan van Dijken

Abstract Magnetoelectric coupling in multiferroic heterostructures offers a promising platform for electric‐field control of magnonic devices based on low‐power spin‐wave transport. Here, electric‐field manipulation of the amplitude and phase of propagating spin waves in a ferromagnetic Fe film on top of a ferroelectric BaTiO 3 substrate is demonstrated experimentally. Electric‐field effects in this composite material system are mediated by strain coupling between alternating ferroelectric stripe domains with in‐plane and perpendicular polarization and fully correlated magnetic anisotropy domains with differing spin‐wave transport properties. The propagation of spin waves across the strain‐induced magnetic anisotropy domains of the Fe film is directly imaged and it is shown how reversible electric‐field‐driven motion of ferroelectric domain walls and pinned anisotropy boundaries turns the spin‐wave signal on and off. Furthermore, linear electric‐field tuning of the spin‐wave phase by altering the width of strain‐coupled stripe domains is demonstrated. The results provide a new route toward energy‐efficient reconfigurable magnonics.

Magnonics

Spin wave

Magnetoelectric effect

10.1002/adma.202100646

Cite

Citations (37)

Spin transport-induced damping of coherent THz spin dynamics in iron

arXiv (Cornell University) (2021)

Liane Brandt Roman Verba Niklas Liebing Mirko Ribow Ilya Razdolski

We study the damping of perpendicular standing spin-waves (PSSWs) in ultrathin Fe films at frequencies up to 2.4 THz. The PSSWs are excited by optically generated ultrashort spin current pulses, and probed optically in the time domain. Analyzing the wavenumber and thickness dependence of the damping, we demonstrate that at sufficiently large wave vectors $k$ the damping is dominated by spin transport effects scaling with k^4 and limiting the frequency range of observable PSSWs. Although this contribution is known to originate in the spin diffusion, we argue that at moderate and large k a more general description is necessary and develop a model where the 'transverse spin mean free path' is the a key parameter, and estimate it to be ~0.5 nm.

Spin wave

Wavenumber

Spin diffusion

10.48550/arxiv.2107.12812

Cite

Citations (0)

Terahertz Spin-to-Charge Conversion by Interfacial Skew Scattering in Metallic Bilayers

Zenodo (CERN European Organization for Nuclear Research) (2021)

Oliver Gueckstock Lukáš Nádvorník Martin Gradhand Tom S. Seifert Genaro Bierhance

Data of the publication "Terahertz Spin-to-Charge Conversion by Interfacial Skew Scattering in Metallic Bilayers" published in Advanced Materials, 33, 2006281 (2021). THz waveforms for a subset and RMS data - corrected for pump incoupling and THz outcoupling - for various F and N metallic bilayers and interface modifications as well as the calculated spin Hall angles for different interfacial impurities are provided.

10.5281/zenodo.5017567

Cite

Citations (0)

Broadband Terahertz Probes of Anisotropic Magnetoresistance Disentangle Extrinsic and Intrinsic Contributions

Physical Review X (2021)

Lukáš Nádvorník Martin Borchert Liane Brandt Richard Schlitz Koen A. de Mare

In magnetic metals, electrical resistance depends on the direction of magnetization relative to the current. New experiments show that this effect does not depend solely on electron collisions, as is typically assumed.

10.1103/physrevx.11.021030

Cite

Citations (32)

Femtosecond formation dynamics of the spin Seebeck effect revealed by terahertz spectroscopy

Nature Communications (2018)

Tom S. Seifert Samridh Jaiswal Joseph Barker Sebastian T. Weber Ilya Razdolski

Understanding the transfer of spin angular momentum is essential in modern magnetism research. A model case is the generation of magnons in magnetic insulators by heating an adjacent metal film. Here, we reveal the initial steps of this spin Seebeck effect with <27fs time resolution using terahertz spectroscopy on bilayers of ferrimagnetic yttrium-iron garnet and platinum. Upon exciting the metal with an infrared laser pulse, a spin Seebeck current $j_\textrm{s}$ arises on the same ~100fs time scale on which the metal electrons thermalize. This observation highlights that efficient spin transfer critically relies on carrier multiplication and is driven by conduction electrons scattering off the metal-insulator interface. Analytical modeling shows that the electrons' dynamics are almost instantaneously imprinted onto $j_\textrm{s}$ because their spins have a correlation time of only ~4fs and deflect the ferrimagnetic moments without inertia. Applications in material characterization, interface probing, spin-noise spectroscopy and terahertz spin pumping emerge.

Ferrimagnetism

Yttrium Iron Garnet

Magnon

10.1038/s41467-018-05135-2

Cite

Citations (82)