A5017358419- Magnetic properties of thin films
- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Quantum and electron transport phenomena
- Graphene research and applications
- Magnetic and transport properties of perovskites and related materials
- Ferroelectric and Piezoelectric Materials
- Theoretical and Computational Physics
- Multiferroics and related materials
- 2D Materials and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Magnetic Properties of Alloys
- Microwave Dielectric Ceramics Synthesis
- Machine Learning in Materials Science
- Quantum many-body systems
- Dielectric materials and actuators
- Electronic and Structural Properties of Oxides
- Quantum, superfluid, helium dynamics
- Dielectric properties of ceramics
- Perovskite Materials and Applications
- Magneto-Optical Properties and Applications
- Magnetic Properties and Applications
- Electron and X-Ray Spectroscopy Techniques
- Heusler alloys: electronic and magnetic properties
University of New Hampshire at Manchester
2024-2025
University of New Hampshire
2015-2024
University of Cologne
2022
Dalian University of Technology
2020-2021
Hatz (Germany)
2019-2020
Molecular Devices
2020
Joint Center for Artificial Photosynthesis
2020
Institute of Art
2020
Technical University of Darmstadt
2012-2017
Johns Hopkins University
2013-2016
Existence of the magnetic monopole is compatible with fundamental laws nature; however, this elusive particle has yet to be detected experimentally. We show theoretically that an electric charge near a topological surface state induces image due magneto-electric effect. The field generated by may experimentally measured, and inverse square law dependence can determined quantitatively. propose effect used realize gas quantum particles carrying fractional statistics, consisting bound states charge.
We study the collective dynamics of Skyrmion crystal in thin films ferromagnetic metals resulting from nontrivial topology. It is shown that current-driven motion reduces topological Hall effect and trajectories bend away direction electric current (the effect). find a new dissipation mechanism noncollinear spin textures can lead to much faster relaxation than Gilbert damping, calculate dispersion phonons crystal, discuss effects impurity pinning Skyrmions.
The notion of non-trivial topological winding in condensed matter systems represents a major area present-day theoretical and experimental research. Magnetic materials offer versatile platform that is particularly amenable for the exploration spin solitons real space such as skyrmions. First identified non-centrosymmetric bulk materials, rapidly growing zoology hosting skyrmions related includes compounds, surfaces, thin films, heterostructures, nano-wires nano-dots. This underscores an...
Abstract The promise of high-density and low-energy-consumption devices motivates the search for layered structures that stabilize chiral spin textures such as topologically protected skyrmions. At same time, recently discovered long-range intrinsic magnetic orders in two-dimensional van der Waals materials provide a new platform discovery novel physics effects. Here we demonstrate Dzyaloshinskii–Moriya interaction Néel-type skyrmions are induced at WTe 2 /Fe 3 GeTe interface. Transport...
We study the Skyrmion dynamics in thin films under a temperature gradient. Our numerical simulations show that both single and multiple Skyrmions crystal move towards high region, which is contrary to particle diffusion. Noticing similar effect domain wall motion, we employ theory based on magnon explain this counterintuitive phenomenon. Unlike driven Skyrmion's topological charge plays an important role, transverse motion observed. turns out be agreement with simulations, qualitatively...
The emergence of a topologically nontrivial vortex-like magnetic structure, the skyrmion, has launched new concepts for memory devices. Extensive studies have theoretically demonstrated ability to encode information bits by using chain skyrmions in one-dimensional nanostripes. Here, we report experimental observation skyrmion FeGe nanostripes high-resolution Lorentz transmission electron microscopy. Under an applied field, observe that helical ground states with distorted edge spins evolve...
Uniquely in Cu2OSeO3, the Skyrmions, which are topologically protected magnetic spin vortex-like objects, display a magnetoelectric coupling and can be manipulated by externally applied electric (E) fields. Here, we explore E-field to Skyrmion lattice phase, study response using neutron scattering. Giant induced rotations of achieved that span range $\sim$25$^{\circ}$. Supporting calculations show an E-field-induced distortion lies behind rotation. Overall, present new approach control makes...
A target Skyrmion is a flux-closed spin texture that has twofold degeneracy and promising as binary state in next generation universal memories. Although its formation nanopatterned chiral magnets been predicted, observation remained challenging. Here, we use off-axis electron holography to record images of Skyrmions 160-nm-diameter nanodisk the magnet FeGe. We compare experimental measurements with numerical simulations, demonstrate switching between two stable degenerate ground states have...
Significantly enhanced energy density is obtained at a low electric field by embedding aligned BaTiO<sub>3</sub> nanowires in polymer matrix <italic>via</italic> new physical-assisted casting method.
Writing, erasing and computing are three fundamental operations required by any working electronic devices. Magnetic skyrmions could be basic bits in promising emerging topological spintronic In particular, chiral magnets have outstanding properties like compact texture, uniform size high mobility. However, creating, deleting driving isolated skyrmions, as prototypes of aforementioned operations, been grand challenge ever since the discovery achieving all these a single device is highly...
Abstract The current-driven movement of magnetic skyrmions along a nanostripe is essential for the advancement and functionality new category spintronic devices resembling racetracks. Despite extensive research into skyrmion dynamics, experimental verification current-induced motion ultra-small within an ultrathin still pending. Here, we unveil individual 80 nm-size in FeGe track with width 100 nm. can move steadily over broad range current densities by using controlled pulse durations as...
Several observational constraints are imposed on the interacting holographic model of dark energy and matter. First we use age parameter today, as given by WMAP results. Subsequently, explained reason why it is possible, recently observed, for an old quasar to be observed in early stages Universe. We discuss this question terms evolution well structure formation. Finally, give a detailed discussion implied CMB low ℓ suppression. As result, has been proved robust with reasonable bounds...
We develop a theory of the magnetic field-induced formation Skyrmion crystal state in chiral magnets two spatial dimensions, motivated by recent discovery Skyrmionic phase magnetization thin film ${\text{Fe}}_{0.5}{\text{Co}}_{0.5}\text{Si}$ and A MnSi. Ginzburg-Landau functional magnet rewritten ${\text{CP}}^{1}$ representation is shown to be convenient framework for analysis states. Phase diagram model at zero temperature gives sequence ground states, helical...
The electrical and dielectric properties of (1 − x )(0.94Bi 1/2 Na TiO 3 –0.06BaTiO )– (K 0.5 NbO ) with = 0, 0.03, 0.09, 0.18 have been investigated by impedance spectroscopy over a wide temperature range. dc conductivity the ceramics follows Arrhenius law an activation energy ranging from ~1.20 to 1.50 eV. Measurements under different atmospheres show materials exhibit n ‐type semiconducting behavior at elevated temperatures. presence highly polarizable phase for all compositions is...
We investigate theoretically the dynamics of magnetization coupled to surface Dirac fermions a three-dimensional topological insulator by deriving Landau-Lifshitz-Gilbert (LLG) equation in presence charge current. Both inverse spin-galvanic effect and Gilbert damping coefficient $\ensuremath{\alpha}$ are related two-dimensional diagonal conductivity ${\ensuremath{\sigma}}_{xx}$ fermion, while Berry phase ferromagnetic moment Hall ${\ensuremath{\sigma}}_{xy}$. The spin-transfer torque...
Significance The rapid growth of data volume demands faster and denser storage devices. noncoplanar swirling spin texture, known as magnetic skyrmion, has potential application in future memory To realize such applications, it is essential to understand the properties individual skyrmion patterned nanoelements. While quite a number theoretical efforts have been made this field, direct experimental demonstration real modeling system challenge. Here, we report visualization cluster states FeGe...
Low levels of so-called “donor-doping” in titanate-based perovskite oxides such as La for Ba, Sr, and Nb Ti (Ba, Sr)TiO3 can significantly reduce the resistivity these typical (d0) dielectric materials expand application areas to positive temperature coefficient resistors, thermoelectrics, conductive wafers thin film substrates, solid oxide fuel cell anode materials. Here, we show low Nb-doping (≤1 at. %) on Ti-site well-known lead-free piezoelectric Na0.5Bi0.5TiO3 (NBT) produces completely...
Hopfions are three-dimensional (3D) topological textures characterized by the integer Hopf invariant ${Q}_{H}$. Here we present realization of a zero-field, stable hopfion spin texture in magnetic system consisting chiral magnet nanodisk sandwiched two films with perpendicular anisotropy. The preimages and numerical calculations ${Q}_{H}$ show that has ${Q}_{H}=1$. Furthermore, another nontrivial state includes monopole-antimonopole pair (MAP) is also stabilized this system. By applying an...
Ionic substitution forms an essential pathway to manipulate the carrier density and crystalline symmetry of materials via ion-lattice-electron coupling, leading a rich spectrum electronic states in strongly correlated systems. Using ferromagnetic metal SrRuO3 as model system, we demonstrate efficient reversible control both through ionic liquid gating induced protonation. The insertion protons electron-dopes SrRuO3, exotic paramagnetic phase transition along with increase proton...