A5007967774- Magnetic properties of thin films
- Theoretical and Computational Physics
- Metallic Glasses and Amorphous Alloys
- Characterization and Applications of Magnetic Nanoparticles
- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Microfluidic and Bio-sensing Technologies
- Electron Spin Resonance Studies
- Advanced Electron Microscopy Techniques and Applications
- Quantum Chromodynamics and Particle Interactions
- Mass Spectrometry Techniques and Applications
- Advanced Materials and Mechanics
- Metal and Thin Film Mechanics
- Anodic Oxide Films and Nanostructures
- Pickering emulsions and particle stabilization
- Quantum Mechanics and Applications
- Lipid metabolism and biosynthesis
- Geomagnetism and Paleomagnetism Studies
- Microstructure and mechanical properties
- Quantum many-body systems
- Lattice Boltzmann Simulation Studies
- Medical Imaging Techniques and Applications
- Micro and Nano Robotics
- Metallurgical and Alloy Processes
Massachusetts Institute of Technology
2024-2025
McGovern Institute for Brain Research
2025
University of California, Santa Cruz
2017-2021
Lawrence Berkeley National Laboratory
2017-2021
University of California, Berkeley
2018
Liquid reconfigurable ferromagnetic materials Ferromagnetic show a permanent magnetic dipole, whereas superparamagnetic ones only properties under an applied field. Some materials, like ferrofluids, liquid-like behavior but do not retain their magnetization in the absence of Liu et al. remnant otherwise magnetite nanoparticles at oil-water interface emulsion droplets (see Perspective by Dreyfus). The could be controlled coupling and uncoupling individual nanoparticles, making it possible to...
The interesting physics and potential memory technologies resulting from topologically protected spin textures such as skyrmions, has prompted efforts to discover new material systems that can host these kind of magnetic structures. Here we use the highly tunable properties amorphous Fe/Gd multilayer films explore lead dipole-stabilized skyrmions skyrmion lattices form competition dipolar field exchange energy. Using both real space imaging reciprocal scattering techniques determined range...
Abstract Among topological solitons, magnetic skyrmions are two-dimensional particle-like objects with a continuous winding of the magnetization, and Hopfions three-dimensional that can be formed from closed loop twisted skyrmion strings. Theoretical models suggest stabilized in frustrated or chiral systems, target skymions transformed into by adapting their perpendicular anisotropy, but experimental verification has been elusive so far. Here, we present an study created Ir/Co/Pt multilayers...
Magnetic monopoles, proposed as elementary particles that act isolated magnetic south and north poles, have long attracted research interest analogs to electric charge. In solid-state physics, a classical analog these elusive has emerged topological excitations within pyrochlore spin ice systems. We present the first real-time imaging of emergent monopole motion in macroscopically degenerate artificial system consisting thermally activated Ising-type nanomagnets lithographically arranged...
The dynamic response of dipole skyrmions in Fe/Gd multilayer films is investigated by ferromagnetic resonance measurements and compared to micromagnetic simulations. We detail thickness temperature dependent studies the observed modes as well effects magnetic field history on resonant spectra. Correlation between phase maps constructed from real-space imaging scattering patterns allows us conclude arise local topological features such but does not depend collective a closed packed lattice...
Inversion symmetry breaking has become a vital research area in modern magnetism with phenomena including the Rashba effect, spin Hall and Dzyaloshinskii-Moriya interaction (DMI)-a vector exchange. The latter one may stabilize chiral textures topologically nontrivial properties, such as Skyrmions. So far, have mainly been studied helimagnets thin ferromagnets heavy-element capping. Here, concept of chirality driven by interfacial DMI is generalized to complex multicomponent systems...
Abstract Magnetic supraparticles (SPs) can be employed as micron‐sized particulate additives in arbitrary objects to serve ID‐tag or recorder of environmental triggers. Combined with magnetic particle spectroscopy (MPS), which enables read‐out the information ambient conditions within seconds, SPs represent a powerful approach equip materials information. The encoded relies on interactions ( intra ‐SP interactions) chosen nanoparticles (NPs). However, possible between inter‐ SP...
We use nano disk arrays with square and honeycomb symmetry to investigate magnetic phases spin correlations of XY dipolar systems at the micro scale. Utilizing magnetization sensitive X-ray photoemission electron microscopy, we probe ground states "order-by-disorder" phenomenon predicted 30 years ago. observe antiferromagnetic striped state in lattices, 6-fold symmetric structures, including trigonal vortex lattices disordered floating vortices, lattice. The frustration lattice causes a...
Target Skyrmions (TSks) are extended topological spin textures with a constant chirality where the rotation of z component magnetization is larger than π. TSks have charge 1 or 0, if Mz goes through nπ n an odd even integer, respectively. up to 4π been imaged via high spatial resolution element-specific x-ray imaging. The were generated by weakly coupling 30 nm thin Permalloy (Ni80Fe20, PY) disks μm diameter asymmetric (Ir nm/Co 1.5 nm/Pt nm) × 7 multilayers that exhibit...
We report a magnetic X-ray microscopy study of the pattern formation circulation in arrays vortices ordered hexagonal and honeycomb lattice. In lattice, we observe at remanence an phase alternating circulations, whereas small regions lines form. A variation edge-to-edge distance shows that size those scales with magnetostatic interaction. Micromagnetic simulations reveal patterns result from flux closure states during nucleation process.
Target skyrmions (TSks) are topological spin textures where the out-of-plane component of magnetization twists an integer number k-π rotations. Based on a magnetic multilayer stack in form n × [CoFeB/MgO/Ta], engineered to host via dipole and DMI energies, we have stabilized 1 π, 2 3 π target by tuning material properties thermal-excitations close room temperature. The nucleated textures, imaged Kerr Magnetic Force Microscopies, stable at zero field robust within range temperatures (tens...
Tunable microwave and millimeter wave oscillators bandpass filters with ultra-low phase noise play a critical role in electronic devices, including wireless communication, microelectronics, quantum computing. Magnetic materials, such as yttrium iron garnet (YIG), possess ferromagnetic resonance tunable up to tens of gigahertz. Here, we report structural magnetic properties single-crystal 60 130 nm-thick YIG films prepared by metal-organic decomposition epitaxy. These films, consisting...
Harnessing high-resolution Lorentz microscopy, in article number 1800199, Robert Streubel and co-workers visualize chiral ferrimagnetic domain walls amorphous films, revealing a composition dependence that potentially enables temperature control of intrinsic wall properties.The reconstructed electron phase (magnetic induction) achiral Bloch is shown here.
Target skyrmions (TSks) are topological spin textures where the out-of-plane component of magnetization twists an integer number $m$-$\pi$ rotations. Based on a magnetic multilayer stack in form $n\times$[CoFeB/MgO/Ta], engineered to host via dipole and DMI energies, we have successfully stabilized 1$\pi$, 2$\pi$ 3$\pi$ target by tuning material properties thermal excitations close room temperature. The nucleated textures, imaged Kerr Magnetic Force Microscopies, stable at zero field robust...