A5064747914- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Quantum and electron transport phenomena
- Heusler alloys: electronic and magnetic properties
- Physics of Superconductivity and Magnetism
- Magnetic Properties and Applications
- Magnetic Properties of Alloys
- Advanced Condensed Matter Physics
- Theoretical and Computational Physics
- Electronic and Structural Properties of Oxides
- Characterization and Applications of Magnetic Nanoparticles
- Magnetism in coordination complexes
- Metal and Thin Film Mechanics
- Diamond and Carbon-based Materials Research
- Quantum, superfluid, helium dynamics
- Microstructure and mechanical properties
- Shape Memory Alloy Transformations
- Topological Materials and Phenomena
- Ferroelectric and Negative Capacitance Devices
- Atomic and Subatomic Physics Research
- nanoparticles nucleation surface interactions
- Cold Atom Physics and Bose-Einstein Condensates
- Nanopore and Nanochannel Transport Studies
- Fuel Cells and Related Materials
- Fusion materials and technologies
Forschungszentrum Jülich
2017-2020
Uppsala University
2014-2019
We present a systematic study of the magnetic properties $\mathrm{L}1{}_{0}$ binary alloys FeNi, CoNi, MnAl, and MnGa via two different density functional theory approaches. Our calculations show large magnetocrystalline anisotropies in order $1\phantom{\rule{0.28em}{0ex}}{\mathrm{MJ}/\mathrm{m}}^{3}$ or higher for MnGa, while FeNi shows somewhat lower value range $0.48--0.77\phantom{\rule{0.28em}{0ex}}{\mathrm{MJ}/\mathrm{m}}^{3}$. Saturation magnetization values...
Abstract Chiral magnetic interactions induce complex spin textures including helical and conical spirals, as well particle-like objects such skyrmions merons. These are the basis for innovative device paradigms give rise to exotic topological phenomena, thus being of interest both applied fundamental sciences. Present key questions address dynamics system emergent defects. Here we analyse micromagnetic in helimagnetic phase FeGe. By combining force microscopy, single-spin magnetometry...
The half-metallic half-Heusler alloy NiMnSb is a promising candidate for applications in spintronic devices due to its low magnetic damping and rich anisotropies. Here we use ferromagnetic resonance (FMR) measurements calculations from first principles investigate how the composition of epitaxially grown influences magnetodynamic properties saturation magnetization $M_S$, Gilbert $\alpha$, exchange stiffness $A$. $M_S$ $A$ are shown have maximum stoichiometric composition, while minimum. We...
We present a direct experimental investigation of the thermal ordering in an artificial analogue asymmetric two-dimensional Ising system composed rectangular array nano-fabricated magnetostatically interacting islands. During fabrication and below critical thickness magnetic material islands are thermally fluctuating thus is able to explore its phase space. Above freeze-in resulting arrested thermalized state for array. Determining we demonstrate genuine which can be analyzed context nearest...
An extended atomistic spin model allowing for studies of the finite temperature magnetic properties alloys is proposed. The obtained by extending Heisenberg Hamiltonian via a parameterization from first principles basis, interpolating both low ferromagnetic and high paramagnetic reference states. This allows us to treat systems with varying degree itinerant character within model. Satisfactory agreement previous theoretical experiments are in terms Curie temperatures properties. proposed not...
Resting on multi-scale modelling simulations, we explore dynamical aspects characterizing magnetic skyrmions driven by spin-transfer-torque towards repulsive and pinning 3
Abstract Understanding interactions of magnetic textures with defects is crucial for applications such as racetrack memories or microwave generators. Such appear on the few nanometer scale, where imaging has not yet been achieved controlled external forces. Here, we establish a method determining via spin-polarized scanning tunneling microscopy in three-dimensional fields. We track vortex core, pushed by forces in-plane fields, and discover that core (~ 10 4 Fe-atoms) gets successively...
Abstract Magnetic skyrmions are prime candidates as information carriers for spintronic devices due to their topological nature and nanometric size. However, unavoidable inhomogeneities inherent any material leads pinning or repulsion of that, in analogy biology concepts, define the phenotype skyrmion-defect interaction, generating complexity motion challenging application future bits information. Here, we demonstrate that atom-by-atom manufacturing multi-atomic defects, being...
It has recently been shown that domain walls (DWs) in ferromagnets can be moved the presence of thermal gradients. In this work we study motion narrow low-dimensional systems when subjected to The system chosen is a monolayer Fe on W(110) which known exhibit large anisotropy while having soft exchange, resulting very wall. performed by means atomistic spin dynamics simulations coupled first-principles calculations. By subjecting gradients observe temperature-dependent movement gradient...
Heusler alloys have been intensively studied due to the wide variety of properties that they exhibit. One these is particular interest for technological applications, i.e., fact some are half-metallic. In following, a systematic study magnetic three different families ${\mathrm{Co}}_{2}\mathrm{Mn}\mathrm{Z},{\text{Co}}_{2}\text{Fe}\text{Z}$, and ${\mathrm{Mn}}_{2}\mathrm{V}\mathrm{Z}$ with...
We investigate numerically the magnetization dynamics of an array nanodisks interacting through magnetodipolar coupling. In presence a temperature gradient, chain reaches nonequilibrium steady state where energy and currents propagate. This effect can be described as flow particle in off-equilibrium discrete nonlinear Schr\"odinger (DNLS) equation. model makes transparent transport properties system allows for precise definition chemical potential precessing spin. The present study proposes...
Relaxation effects are of primary importance in the description magnetic excitations, leading to a myriad methods addressing phenomenological damping parameters. In this work, we consider several well-established forms calculating intrinsic Gilbert within unified theoretical framework, mapping out their connections and approximations required derive each formula. This scheme enables direct comparison different on same footing consistent evaluation range validity. Most lead very similar...
By means of first principles calculations, we have systematically investigated how the magnetodynamic properties Gilbert damping, magnetization and exchange stiffness are affected when permalloy (Py) (Fe$_{0.19}$Ni$_{0.81}$) is doped with 4d or 5d transition metal impurities. We find that trends in damping can be understood from relatively few basic parameters such as density states at Fermi level, spin-orbit coupling impurity concentration. % The temperature dependence found to very weak...
Doping ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ by magnetic ions represents an interesting problem since it may break the time-reversal symmetry needed to maintain topological insulator character. Mn dopants in represent one of most studied examples here. However, there is a lot open questions regarding their ordering. In experimental literature different Curie temperatures or no ferromagnetic order at all are reported for comparable concentrations. This suggests that ordering phenomena complex...
${\text{La}}_{x}{\text{Ca}}_{1\ensuremath{-}x}{\text{MnO}}_{3}$ (LCMO) has been studied in the framework of density functional theory (DFT) using Hubbard-$U$ correction. We show that formation spin polarons different configurations is possible G-type antiferromagnetic phase. also spin-polaron (SP) solutions are stabilized due to an interplay magnetic and lattice effects at lower La concentrations mostly contribution larger concentrations. Our results indicate development SPs unfavorable C-...
The static and dynamic properties of spin polarons in La-doped ${\text{CaMnO}}_{3}$ are explored theoretically, by means an effective low-energy Hamiltonian. All parameters the Hamiltonian evaluated from first-principles theory. is used to investigate temperature stability as well response external applied electric field, for bulk, surface, single two-dimensional layers. Technically this involves atomistic spin-dynamics simulations combination with kinetic Monte Carlo simulations. Where a...