A5089674083- Magnetic properties of thin films
- Multiferroics and related materials
- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Advanced Electron Microscopy Techniques and Applications
- 2D Materials and Applications
- Graphene research and applications
- Advanced Condensed Matter Physics
- Quantum and electron transport phenomena
- Ion-surface interactions and analysis
- X-ray Spectroscopy and Fluorescence Analysis
- Force Microscopy Techniques and Applications
- Advanced X-ray Imaging Techniques
- Metallic Glasses and Amorphous Alloys
- Atomic and Subatomic Physics Research
- Iron-based superconductors research
- Semiconductor materials and interfaces
- Electron and X-Ray Spectroscopy Techniques
- Chemical and Physical Properties of Materials
- MXene and MAX Phase Materials
- Advanced Memory and Neural Computing
- Surface and Thin Film Phenomena
- Magnetic Properties and Applications
- Quantum Dots Synthesis And Properties
Cornell University
2020-2025
Efficient manipulation of antiferromagnetically coupled materials that are integration-friendly and have strong perpendicular magnetic anisotropy (PMA) is great interest for low-power, fast, dense storage computing. Here, we report a distinct, giant bulk damping-like spin–orbit torque in strong-PMA ferrimagnetic Fe100−xTbx single layers (composition-uniform, amorphous, sputter-deposited). For sufficiently thick layers, this constant the efficiency per unit layer thickness, ξDLj/t, with...
Abstract Cryo-EM is a powerful tool in structural biology, providing insights through techniques like single-particle analysis (SPA) and cryogenic electron tomography (cryo-ET). In thick specimens, challenges arise as an exponentially larger fraction of the transmitted electrons lose energy from inelastic scattering can no longer be properly focused result chromatic aberrations post-specimen optics. Rather than filtering out at price reducing potential signal, done energy-filtered...
We report spin-torque ferromagnetic resonance studies of the efficiency damping-like (ξDL) spin–orbit torque exerted on an adjacent ferromagnet film by current flowing in epitaxial (001) and (110) IrO2 thin films. possesses Dirac nodal lines (DNLs) band structure that are gapped coupling, which could enable a very high spin Hall conductivity, σSH. find films do exhibit exceptionally ξDL ranging from 0.45 at 293 K to 0.65 30 K, sets lower bounds σSH be 1.9 × 105 3.75 Ω–1 m–1, respectively, 10...
Disordered iron germanium (FeGe) has recently garnered interest as a testbed for variety of magnetic phenomena well use in memory and logic applications. This is partially owing to its ability host skyrmions antiskyrmions—nanoscale whirlpools moments that could serve information carriers spintronic devices. In particular, tunable skyrmion–antiskyrmion system may be created through precise control the defect landscape B20-phase FeGe, motivating development methods systematically tune disorder...
Abstract To overcome the spatial resolution limit set by aperture-limited diffraction in traditional scanning transmission electron microscopy, microscopists have developed ptychography enabled iterative phase retrieval algorithms and high-dynamic-range pixel array detectors. Current detector designs are limited data rate off chip, so a high-pixel-count has proportionally lower frame than few-segment detectors used for differential contrast (DPC) imaging. This slower acquisition speed leads...
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....
Abstract Skyrmions and antiskyrmions are nanoscale swirling textures of magnetic moments formed by chiral interactions between atomic spins in noncentrosymmetric materials multilayer films with broken inversion symmetry. These quasiparticles interest for use as information carriers next-generation, low-energy spintronic applications. To develop skyrmion-based memory logic, we must understand skyrmion-defect two main goals—determining how skyrmions navigate intrinsic material defects...
The heterostructures of 2D magnets and topological insulators are attractive candidates for quantum anomalous hall effect highly-efficient spin-orbit torque switching. To better study these phenomena, it will be crucial to synthesize epitaxial scalability while maintaining high-quality interfaces preserve the surface states having Curie temperature (T${}_{C}$) above room temperature. Here, authors utilize molecular beam epitaxy tune T${}_{C}$ in van der Waals (vdW) magnet...
We present measurements of thermally generated transverse spin currents in the topological insulator Bi 2 Se 3 , thereby completing interconversions among full triad thermal gradients, charge currents, and currents. accomplish this by comparing Nernst magneto-thermopower to Hall magnetoresistance for bilayers /CoFeB. find that does generate substantial driven A lower bound ratio current density gradient is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">...
Abstract Strong damping‐like spin‐orbit torque (τ DL ) has great potential for enabling ultrafast energy‐efficient magnetic memories, oscillators, and logic. So far, the reported τ exerted on a thin‐film magnet must result from an externally generated spin current or internal non‐equilibrium polarization in non‐centrosymmetric GaMnAs single crystals. Here, first time very strong, unexpected is demonstrated flow within ferromagnetic layers of chemically disordered, face‐centered‐cubic CoPt....
We demonstrate advantages of samples made by mechanical stacking exfoliated van der Waals materials for controlling the topological surface state a three-dimensional insulator (TI) via interaction with an adjacent magnet layer. assemble bilayers pristine interfaces using flakes TI BiSbTeSe2 and Cr2Ge2Te6, thereby avoiding problems caused interdiffusion that can affect top-down deposition methods. The exhibit anomalous Hall effect (AHE) abrupt hysteretic switching. For first time in composed...
Magnetic van der Waals heterostructures provide a unique platform to study magnetism and spintronics device concepts in the two-dimensional limit. Here, we report studies of exchange bias from antiferromagnet CrSBr acting on ferromagnet Fe3GeTe2 (FGT). The orientation is along in-plane easy axis CrSBr, perpendicular out-of-plane anisotropy FGT, inducing strongly tilted magnetic configuration FGT. Furthermore, provides sufficient symmetry breaking allow deterministic spin-orbit torque...
A promising architecture for next-generation, low energy spintronic devices uses skyrmions -- nanoscale whirlpools of magnetic moment as information carriers. Notably, schemes racetrack memory have been proposed in which and antiskyrmions, their antiparticle, serve the logical bits 1 0. However, major challenges exist to designing skyrmion-antiskyrmion based computing. The presence both particles one material is often mutually exclusive such that few systems identified they coexist, these...
Journal Article Detection Limits for Imaging Chiral Magnetic Materials with 4-Dimensional Lorentz Scanning Transmission Electron Microscopy Get access Xiyue S Zhang, Zhang School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA Search other works by this author on: Oxford Academic Google Scholar Kayla X Nguyen, Nguyen USADepartment Science Engineering, University Illinois Urbana-Champaign, Urbana, IL, Emrah Turgut, Turgut USATaiwan Semiconductor Manufacturing Company,...
Magnetic skyrmions hold promise for spintronic devices. To explore the dynamical properties of in devices, a nanoscale method to image spin textures response stimulus is essential. Here, we apply technique operando electrical current pulsing chiral magnetic devices Lorentz transmission electron microscope. In ferromagnetic multilayers with interfacial Dzyaloshinskii–Moriya interaction, study creation and annihilation localized by point-like pinning sites due defects. Using combination...
Efficient manipulation of antiferromagnetically coupled materials that are integration-friendly and have strong perpendicular magnetic anisotropy (PMA) is great interest for low-power, fast, dense storage computing. Here, we report a distinct, giant bulk damping-like spin-orbit torque in strong-PMA ferrimagnetic Fe100-xTbx single layers (composition-uniform, amorphous, sputter-deposited). For sufficiently-thick layers, this constant the efficiency per unit layer thickness, {\xi}_DL^j/t, with...
The study of nanoscale chiral magnetic order in polycrystalline materials with a strong Dzyaloshinkii-Moriya interaction (DMI) is interesting for the observation phenomena at grain boundaries and interfaces. One such material sputter-deposited B20 FeGe on Si, which has been actively investigated as basis low-power, high-density memory technology scalable platform. Although conventional Lorentz electron microscopy provides requisite spatial resolution to probe textures single-crystal FeGe,...
Heterostructures of two-dimensional (2D) van der Waals (vdW) magnets and topological insulators (TI) are substantial interest as candidate materials for efficient spin-torque switching, quantum anomalous Hall effect, chiral spin textures. However, since many the vdW have Curie temperatures below room temperature, we want to understand how can be modified stabilize their magnetic ordering higher temperatures. In this work, utilize molecular beam epitaxy systematically tune temperature ($T_C$)...
Skyrmions and antiskyrmions are nanoscale swirling textures of magnetic moments formed by chiral interactions between atomic spins in non-centrosymmetric materials multilayer films with broken inversion symmetry. These quasiparticles interest for use as information carriers next-generation, low-energy spintronic applications. To develop skyrmion-based memory logic, we must understand skyrmion-defect two main goals -- determining how skyrmions navigate intrinsic material defects to engineer...
We report measurements demonstrating that when the Neel vector of collinear antiferromagnet RuO2 is appropriately canted relative to sample plane, generates a substantial out plane damping-like torque. The are in good accord with predictions an electric field, E applied spin split band structure it can cause strong transverse current even absence spin-orbit coupling. This produces characteristic changes all three components induced torque as function angle crystal axes, corresponding well...
We complete measurements of interconversions among the full triad thermal gradients, charge currents, and spin currents in topological insulator Bi$_2$Se$_3$ by quantifying efficiency with which gradients can generate transverse currents. accomplish this comparing Nernst magneto-thermopower to Hall magnesistance for bilayers Bi$_2$Se$_3$/CoFeB. find that does substantial thermally-driven A lower bound ratio current gradient is $J_s/\nabla_x T$ = (4.9 $\pm$ 0.9) $\times$ 10$^{6}$ ($\hbar/2e$)...