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Search Publications by: Hans Nembach (Assoc)

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Displaying 1 - 25 of 66

Symmetry-dependent ultrafast manipulation of nanoscale magnetic domains

December 23, 2022
Nanna Hagstrom, Rahul Jangid, F. N. U. Meera, Diego Turenne, Jeffrey Brock, Erik Lamb, Boyan Stoychev, Justine Schlappa, Natalia Gerasimova, Benjamin Van Kuiken, Rafael Gort, Laurent Mercadier, Loic Le Guyader, Andrey Samartsev, Andreas Scherz, Giuseppe Mercurio, Hermann Durr, Alexander Reid, Monika Arora, Hans Nembach, Justin Shaw, Emmanuelle Jal, Eric Fullerton, Mark Keller, Roopali Kukreja, Stefano Bonetti, Thomas J. Silva, Ezio Iacocca
Symmetry is a powerful concept in physics, but its applicability to far-from-equilibrium states is still being understood. Recent attention has focused on how far-from-equilibrium states lead to spontaneous symmetry breaking. Conversely, ultrafast optical

Ultrafast perturbation of magnetic domains by optical pumping in a ferromagnetic multilayer

October 19, 2022
Dmitriy Zusin, Ezio E. Iacocca, Loic Le Guyader, Alexander H. Reid, William Schlotter, TianMin Liu, Daniel Higley, Giacomo Coslovich, Scott F. Wandel, Phoebe Tengdin, Sheena K. Patel, Anatoly Shabalin, Nelson Hua, Stjepan Hrkac, Hans Nembach, Justin Shaw, Sergio Montoya, Adam Blonsky, Christian Gentry, Mark Hoefer, Margaret M. Murnane, Henry C. Kapteyn, Eric E. Fullerton, Oleg Shpyrko, Hermann Durr, Thomas J. Silva
Ultrafast optical pumping of spatially nonuniform magnetic textures is known to induce far-from-equilibrium spin transport effects. Here, we use ultrafast x-ray diffraction with unprecedented dynamic range to study the laser-induced dynamics of labyrinth

Megahertz-rate Ultrafast X-ray Scattering and Holographic Imaging at the European XFEL

August 23, 2022
Thomas J. Silva, Hans Nembach, Mark Keller, Justin Shaw, Nanna Hagstrom, michael schneider, Nico Kerber, Alexander Yaroslavtsev, Erick Parra, Eric Fullerton, Oleg Shpyrko, Christian Gutt, Hermann Durr, Ezio Iacocca, Roopali Kukreja, stefano Bonetti, Emmanuelle Jal
The advent of X-ray free-electron lasers (XFELs) has revolutionized fundamental science, from atomic to condensed matter physics, from chemistry to biology, giving researchers access to X-rays with unprecedented brightness, coherence, and pulse duration

Imaging of Magnetic Excitations in Nanostructures with Microwave Near-Field Microscopy

November 25, 2021
Samuel Berweger, Robert Tyrrell-Ead, Houchen Chang, Mingzhong Wu, Hong Tang, Hans Nembach, Karl Stupic, Stephen E. Russek, Thomas Mitchell (Mitch) Wallis, Pavel Kabos
We present images of spin-wave excitations in a patterned yttrium iron garnet (YIG) thin film obtained by use of near-field microwave microscopy, which can achieve spatial resolution as high as 50 nm. Visualization of magnetic excitations is an enticing

Comparison of measured and simulated spin-wave mode spectra of magnetic nanostructures

January 6, 2021
Hans Nembach, Robert McMichael, Michael Schneider, Justin Shaw, Thomas J. Silva
Motivated by the importance of magnetization dynamics in nanomagnets for the development and optimization of magnetic devices and sensors, we measured and modeled spin wave spectra in patterned elliptical nanomagnets. Ferromagnetic resonance spectra for

Nonlinear losses in magnon transport due to four-magnon scattering

May 25, 2020
T. Hula, K. Schultheiss, A. Budzakov, L. Korber, M. Bejarano, L. Flacke, L. Liensberger, M. Weiler, Justin Shaw, Hans Nembach, J. Fassbender, H. Schultheiss
We report on the impact of nonlinear four-magnon scattering on magnon transport in microstructured Co 25Fe 75 waveguides with low magnetic damping. We determine the magnon propagation length with microfocused Brillouin light scattering over a broad range

Tuning interfacial Dzyaloshinskii-Moriya interactions in thin amorphous ferrimagnetic alloys

May 4, 2020
Yassine Quessab, Jun-Wen Xu, Chung Ting Ma, W. Zhou, Grant A. Riley, Justin Shaw, Hans Nembach, S. J. Poon, Andrew D. Kent
Skyrmions can be stabilized in magnetic systems with broken inversion symmetry and chiral interactions, such as Dzyaloshinskii-Moriya interactions (DMI). Further, compensation of magnetic moments in ferrimagnetic materials can significantly reduce magnetic

All-optical spin transfer between elemental sublattices in half-metallic Co2MnGe Heusler compound within the femtosecond laser excitation pulse

January 17, 2020
Phoebe Tengdin, Christian Gentry, Adam Blonsky, Dmitriy Zusin, Michael Gerrity, Lukas Hellbruck, Moritz Hofherr, Justin Shaw, Yaroslav Kvashnin, Erna K. Delczeg-Czirjak, Monika Arora, Hans Nembach, Thomas J. Silva, Stefan Mathias, Martin Aeschliman, Henry C. Kapteyn, Danny Thonig, Konstantinos Koumpouras, Olle Eriksson, Margaret M. Murnane
Heusler compounds are exciting materials for future spintronics applications because they display a wide range of tunable electronic and magnetic interactions. Here, we use a femtosecond laser to directly transfer spin polarization from one element to

Ultrafast optically induced spin transfer in ferromagnetic alloys

January 17, 2020
Moritz Hofherr, Soren Hauser, J. K. Dewhurst, Phoebe Tengdin, S Sakshath, Hans Nembach, Tobias Weber, Justin Shaw, Thomas J. Silva, H C. Kapteyn, M Cinchetti, B Rethfeld, M M. Murnane, D Steil, B Stadtmuller, S Sharma, Martin Aeschlimann, S Mathias
The vision of using light to manipulate electronic and spin excitations in materials on their fundamental time and length scales requires new approaches in experiment and theory to observe and understand these excitations. The ultimate speed limit for all

High spin-wave propagation length consistent with low damping in a metallic ferromagnet

August 31, 2019
L. Flacke, L. Liensberger, Matthias Althammer, Hans Huebl, Stephan Gepr?ags, Katrin Schultheiss, Aleksandr Buzdakov, T. Hula, H. Schultheiss, Eric R. Edwards, Hans Nembach, Justin Shaw, Rudolf Gross, M. Weiler
We report ultralow intrinsic magnetic damping in Co 25Fe 75 heterostructures, reaching the low 10 -4 regime at room temperature. By using a broadband ferromagnetic resonance technique in out-of-plane geometry, we extracted the dynamic magnetic properties

Magnetoelasticity of Co 25 Fe 75 thin films

August 20, 2019
Daniel Schwienbacher, Matthias Pernpeintner, Lukas Liensberger, Eric R. Edwards, Hans Nembach, Justin Shaw, Mathias Weiler, Rudolf Gross, Hans Huebl
We investigate the magnetoelastic properties of Co 25Fe 75 and Co 10Fe 90 thin films by measuring the mechanical properties of a doubly clamped string resonator covered with multilayer stacks containing these films. For the magnetostrictive constants, we

Co 25 Fe 75 Thin Films with Ultralow Total Damping

May 13, 2019
Eric R. Edwards, Hans T. Nembach, Justin M. Shaw
We measure the dynamic properties of Co 25Fe 75 thin films grown by dc magnetron sputtering. Using ferromagnetic resonance spectroscopy, we demonstrate an ultralow total damping parameter in the out-of-plane configuration of

Domain-wall motion and interfacial Dzyaloshinskii-Moriya interactions in Pt/Co/Ir(tIr)/Ta multilayers

March 7, 2019
Kowsar Shahbazi, Joo-Von Kim, Hans Nembach, Justin Shaw, Andreas Bischof, Marta Rossell, Vincent Jeudy, Thomas A. Moore, Christopher H. Marrows
The interfacial Dzyaloshinskii-Moriya interaction (DMI) is important for chiral domain walls (DWs) and for stabilizing magnetic skyrmions. We study the effects of introducing increasing thicknesses of Ir, from zero to 2 nm, into a Pt/Co/Ta multilayer

Inhomogeneous magnon scattering during ultrafast demagnetization

October 25, 2018
Ronny J. Knut, Erna Delczeg-Czirjak, Somnath Jana, Justin M. Shaw, Hans T. Nembach, Yaroslav Kvashnin, Robert Stefaniuk, Rameez Malik, Patrik Grychtol, Dmitriy Zusin, Christian Gentry, Raghuveer Chimata, Manuel Pereiro, Johan Soderstrom, Emrah Turgut, Martina Ahlberg, Johan Akerman, H C. Kapteyn, Margaret M. Murnane, Dario A. Arena, Olle Eriksson, Olof Karis, Thomas J. Silva
Ni 0.8Fe 0.2 (Py) and Py alloyed with Cu exhibit intriguing ultrafast demagnetization behavior, where the Ni magnetic moment shows a delayed response relative to the Fe, an effect which is strongly enhanced by Cu alloying. We have studied a broad range of

Localization of Fe d-states in Ni-Fe-Cu alloys and implications for ultrafast demagnetization

October 20, 2018
Ronny J. Knut, Erna Delczeg, Justin Shaw, Hans Nembach, Patrik Grychtol, Dmitriy Zusin, Christian Gentry, Emrah Turgut, Henry C. Kapteyn, Margaret M. Murnane, Dario A. Arena, Olle Eriksson, Olof Karis, Thomas J. Silva
Ni 80Fe 20 (Py) and Py-Cu exhibit intriguing ultrafast demagnetization behavior, where the Ni magnetic moment shows a delayed response relative to the Fe [S. Mathias et al., PNAS \bf 109}, 4792 (2012)]. To unravel the mechanism responsible for this

Magnetic properties in ultra-thin 3d transition metal alloys II: experimental verification of quantitative theories of damping and spin-

April 7, 2018
Martin A. Schoen, Juriaan Lucassen, Hans T. Nembach, Thomas J. Silva, Bert Koopmans, Christian Back, Justin M. Shaw
A systematic study of the Gilbert damping is performed via ferromagnetic resonance for the disordered crystalline binary 3d transition metal alloys NiCo, NiFe and CoFe over the whole range of alloy compositions. After accounting for the inhomogeneous

Magnetic properties of ultra-thin 3d transition metal alloys I: spin and orbital moments and confirmation of Slater-Pauling theory

April 7, 2018
Martin A. Schoen, Juriaan Lucassen, Hans T. Nembach, Thomas J. Silva, Bert Koopmans, Christian Back, Justin M. Shaw
The structure and static magnetic properties - saturation magnetization, perpendicular anisotropy, Landé g-factor, and orbital magnetization - of thin film 3d transition metal alloys are determined over the full range of alloy compositions, via X-ray

Determination of spin Hall effect and spin diffusion length of Pt from self-consistent fitting of damping enhancement and inverse spin-orbit torque measurements

March 22, 2018
Andy Berger, Eric R. Edwards, Hans T. Nembach, Olof Karis, Mathias Weiler, Thomas J. Silva
Understanding the evolution of spin-orbit torque (SOT) with increasing heavy-metal thickness in ferromagnet/normal metal (FM/NM) bilayers is critical for the development of magnetic memory based on SOT. However, several experiments have revealed an

Magnetic damping in sputtered Co2MnGe Heusler compounds with A2, B2 and L21 order: Experiment and Theory

March 19, 2018
Justin M. Shaw, Eric R. Edwards, Martin A. Schoen, Michael L. Schneider, Matthew R. Pufall, Thomas J. Silva, Hans T. Nembach, Erna Delczeg
We show that very low values of the magnetic damping parameter can be achieved in sputter deposited poly-crystalline films of Co2MnGe annealed at relatively low temperatures ranging from 240 oC to 400 oC. Damping values as low as 0.0014 are achieved with

Inductive detection of fieldlike and dampinglike ac inverse spin-orbit torques in ferromagnet/normal-metal bilayers

March 15, 2018
Andy Berger, Eric R. Edwards, Hans T. Nembach, Justin M. Shaw, Alexy D. Karenowska, Mathias Weiler, Thomas J. Silva
Phenomena that result from strong spin-orbit coupling (SOC) at ferromagnet/normal metal (FM/NM) interfaces hold great promise for the development of efficient and scalable spintronic devices. SOC drives non-equilibrium spin-charge conversion, manifest as