A5050529343- Magnetic properties of thin films
- Laser-Matter Interactions and Applications
- Magnetic Properties and Applications
- Advanced Electron Microscopy Techniques and Applications
- Magnetic Properties of Alloys
- Advanced Chemical Physics Studies
- Magneto-Optical Properties and Applications
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Characterization and Applications of Magnetic Nanoparticles
- Spectroscopy and Quantum Chemical Studies
- Advanced Fiber Laser Technologies
- Diamond and Carbon-based Materials Research
- Surface and Thin Film Phenomena
- Theoretical and Computational Physics
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
- Terahertz technology and applications
- Bluetooth and Wireless Communication Technologies
- Topological Materials and Phenomena
- Thermal properties of materials
- Rare-earth and actinide compounds
- Ion-surface interactions and analysis
- Boron and Carbon Nanomaterials Research
- Crystallography and Radiation Phenomena
Oklahoma State University Oklahoma City
2020-2023
Oklahoma State University
2019-2023
Taiwan Semiconductor Manufacturing Company (Taiwan)
2022-2023
Cornell University
2016-2022
Taiwan Semiconductor Manufacturing Company (United States)
2022
Joint Institute for Laboratory Astrophysics
2012-2018
University of Colorado Boulder
2012-2017
National Institute of Standards and Technology
2015
University of Colorado System
2015
We describe a hybrid pixel array detector (EMPAD - electron microscope detector) adapted for use in applications, especially as universal scanning transmission microscopy. The 128 x consists of 500 um thick silicon diode bump-bonded pixel-by-pixel to an application-specific integrated circuit (ASIC). in-pixel circuitry provides 1,000,000:1 dynamic range within single frame, allowing the direct beam be imaged while still maintaining sensitivity. A 1.1 kHz framing rate enables rapid data...
The study of ultrafast dynamics in magnetic materials provides rich opportunities for greater fundamental understanding correlated phenomena solid-state matter, because many the basic microscopic mechanisms involved are as-yet unclear and still being uncovered. Recently, two different possible have been proposed to explain laser induced magnetization dynamics: spin currents spin-flip scattering. In this work, we use multilayers Fe Ni with metals insulators as spacer material conclusively...
The underlying physics of all ferromagnetic behavior is the cooperative interaction between individual atomic magnetic moments that results in a macroscopic magnetization. In this work, we use extreme ultraviolet pulses from high-harmonic generation as an element-specific probe ultrafast, optically driven, demagnetization Fe-Ni alloy (permalloy). We show for times shorter than characteristic timescale exchange coupling, magnetization Fe quenches more strongly Ni. Then start to randomize,...
Strong-field ionization provides fundamental insight into light-matter interactions, encoding the structure of atoms and molecules on sub\aa{}ngstr\"om subfemtosecond scales. In this Rapid Communication, we explore an important regime: strong-field by two-color circularly polarized laser fields. contrast to past work using linearly drivers, probe electron trajectories that are driven in a two-dimensional plane, thus separating tunneling angle from rescattering angle. This allows us make...
Ultrashort pulses of extreme ultraviolet light from high-harmonic generation are a new tool for probing coupled charge, spin, and phonon dynamics with element specificity, attosecond pump-probe synchronization, time resolution few femtoseconds in tabletop apparatus. In this paper, we address an important question magneto-optics that has implications understanding magnetism on the fastest scales: Is signal transverse magneto-optical Kerr effect at M2,3 edges magnetic material purely or is it...
The excitation of a ferromagnetic film by femtosecond laser pulse causes an unexpectedly fast quenching the film's magnetization on subpicosecond time scales. microscopic physical mechanisms responsible for this remain scientific puzzle. authors employ extreme ultraviolet pulses produced high harmonic generation to follow how thin cobalt evolves after 40-fs pulse. By measuring time-, energy-, and angle-resolved magneto-optical response Co films across ${M}_{2,3}$ absorption edge, they obtain...
Electrical manipulation of magnetization without an external magnetic field is critical for the development advanced non-volatile magnetic-memory technology that can achieve high memory density and low energy consumption. Several recent studies have revealed efficient out-of-plane spin-orbit torques (SOTs) in a variety materials field-free type-z SOT switching. Here, we report on corresponding type-x configuration, showing significant in-plane unconventional spin polarizations from sputtered...
Phase matching of circularly polarized high-order harmonics driven by counter-rotating bi-chromatic lasers was recently predicted theoretically and demonstrated experimentally. In that work, phase analyzed assuming the total energy, spin angular momentum linear photons participating in process are conserved. Here we propose a new perspective on high harmonics. We derive an extended condition requiring propagation between classical vectorial laser pump fields. This allows us to include...
What does the diffraction pattern from a single atom look like? How it differ scattering long-range potential? With development of new high-dynamic range pixel array detectors to measure complete momentum distribution, these questions have immediate relevance for designing and understanding momentum-resolved imaging modes. We explore asymptotic limits short-range potentials. use simple quantum mechanical model explain general probability distribution in both real reciprocal space. Features...
We use short wavelength extreme ultraviolet light to independently measure the mechanical properties of disparate layers within a bilayer film for first time, with single-monolayer sensitivity. show that in Ni/Ta nanostructured systems, while their density ratio is not meaningfully changed from expected bulk, elastic are significantly modified, where nickel softens tantalum stiffens, relative bulk counterparts. In particular, presence or absence Ta capping layer influences Ni film. This...
Although chiral magnetic materials have emerged as a potential ingredient in future spintronic memory devices, there are few comprehensive studies of properties scalably grown thin films. We present growth, systematic physical and characterization, microwave absorption spectroscopy B20 FeGe also perform micromagnetic simulations apply analytical theory to understand the dynamical behavior this material. find resonance features both helical field-polarized states, which well explained by...
The study of nanoscale chiral magnetic order in polycrystalline materials with a strong Dzyaloshinskii-Moriya interaction is interesting for the observation phenomena at grain boundaries and interfaces. This especially true materials, which can be grown using scalable techniques, scalability promising future device applications. One such material sputter-deposited B20 $\mathrm{Fe}\mathrm{Ge}$ on $\mathrm{Si}$, actively investigated as basis low-power high-density memory technology platform....
Resonant spin dynamics of topological textures are correlated with their nature, which can be employed to understand this nature. In study, we present resonant three-dimensional texture, i.e., Neel and Bloch hopfions. Using micromagnetic simulations, stabilize hopfions bulk interfacial Dzyaloshinskii-Moriya interaction (DMI), respectively. We identify the ground state configuration both hopfions, effects anisotropies, geometric confinements, demagnetizing fields. To confirm Hopf number is...
Energy efficient computing hardware has played an instrumental role in enabling novel abundant data applications and transformative new user experiences. As we look forward, many emerging nonvolatile memory technologies have been proposed to further improve the energy efficiency of tomorrow's systems. Spin–orbit torque magnetoresistive random access (SOT-MRAM) its variants are one class technology, which promises static (SRAM)-like performance at a higher bit-cell density. In this article,...
Understanding spin-wave dynamics in chiral magnets is a key step for the development of high-speed, based spintronic devices that take advantage and topological spin textures their operation. Here, we present an experimental theoretical study cubic B20 FeGe single crystal. Using combination waveguide microwave absorption spectroscopy (MAS), micromagnetic simulations, analytical theory, identify resonance all magnetic phases (field polarized, conical, helical, skyrmion phases). Because...
Chiral magnetic $\mathrm{M}{\mathrm{n}}_{x}\mathrm{F}{\mathrm{e}}_{1\ensuremath{-}x}\mathrm{Ge}$ compounds have an antisymmetric exchange interaction that is tunable with the manganese stoichiometric fraction, $x$. Although millimeter-scale, polycrystalline bulk samples of this family been produced, thin-film versions these materials will be necessary for devices. In study, we demonstrate growth epitaxial thin films on Si(111) substrates a pure B20 crystal structure in fraction range $x$...
The study of interfacial Dzyaloshinskii-Moriya interaction (DMI) in perpendicularly magnetized structurally asymmetric heavy metal/ferromagnet multilayer systems is high importance due to the formation chiral magnetic textures presence DMI. Here, we report impact cobalt oxidation at Co/AlOxinterface Pt/Co/AlOxtrilayer structures on DMI by varying post-growth annealing time, Al thickness and substrate. To quantify employed magneto-optical imaging domain wall expansion, hysteresis loop shift,...
Journal Article 4D-STEM for Quantitative Imaging of Magnetic Materials with Enhanced Contrast and Resolution Get access Kayla X Nguyen, Nguyen School Applied Engineering Physics, Cornell University, Ithaca, NY, USA Search other works by this author on: Oxford Academic Google Scholar Prafull Purohit, Purohit Department Robert Hovden, Hovden Emrah Turgut, Turgut Mark W Tate, Tate Lena F Kourkoutis, Kourkoutis USAKavli Institute at Nanoscale Science, NY Gregory D Fuchs, Fuchs Sol M Gruner,...
Contribution: A do-it-yourself (DIY) light wave sensing (LWS) and communication project was developed to generate interest clarify basic electromagnetic (EM) wireless sensing/communication concepts among students at different education levels from middle school undergraduate. This article demonstrates the nature of its preliminary effectiveness. Background: Concepts in are generally considered hard comprehend being underpinned only by theoretical coursework occasional simulations. Further,...
In this study, micromagnetic simulations of a magnetic skyrmion reshuffling chamber for probabilistic computing applications are performed. The shuffling is modeled with custom current density masking technique to capture variation, grain boundary variations, and anisotropy changes. results show that the oscillatory dynamics contribute system's stochasticity, allowing uncorrelated signals be achieved single chamber. Our findings indicate generally at all temperatures simulated, diameter...