A5087539102- Magnetic properties of thin films
- Theoretical and Computational Physics
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Magnetic Properties and Applications
- Quantum and electron transport phenomena
- Advanced Physical and Chemical Molecular Interactions
- Rare-earth and actinide compounds
- ZnO doping and properties
- Iron-based superconductors research
- Multiferroics and related materials
- Topological and Geometric Data Analysis
- Magnetism in coordination complexes
- Electronic and Structural Properties of Oxides
- Magneto-Optical Properties and Applications
- Machine Learning in Materials Science
- Molecular spectroscopy and chirality
- Quantum, superfluid, helium dynamics
- Advanced NMR Techniques and Applications
- Organic and Molecular Conductors Research
- Advanced Chemical Physics Studies
- Chemical and Physical Properties of Materials
- 2D Materials and Applications
- Spectroscopy and Quantum Chemical Studies
KTH Royal Institute of Technology
2016-2025
Nordic Institute for Theoretical Physics
2017-2025
Stockholm University
2020-2023
Sapienza University of Rome
2014-2016
Institute for Complex Systems
2014-2016
Superconducting and other Innovative Materials and Devices Institute
2011-2012
Uppsala University
2008-2012
Istituto Nazionale per la Fisica della Materia
2012
We present a method for performing atomistic spin dynamic simulations. A comprehensive summary of all pertinent details the simulations such as equations motions, models including temperature, methods extracting data and numerical schemes is given. The can be applied in first principles mode, where interatomic exchange calculated self-consistently, or it with frozen parameters estimated from experiments fixed spin-configuration. Areas potential applications to different magnetic questions...
We propose a general theoretical framework for ultrafast laser-induced spin dynamics in multisublattice magnets. distinguish relaxation of relativistic and exchange origin show that when the former dominates, nonequivalent sublattices have distinct despite their strong coupling. Even more interesting, dominated regime can highly counterintuitive transitions between parallel antiparallel alignment. This allows us to explain recent experiments with antiferromagnetically coupled sublattices,...
PdFe/Ir(111) has attracted tremendous attention for next-generation spintronics devices due to existence of magnetic skyrmions with the external field. Our density functional theoretical calculations in combination spin dynamics simulation suggest that spiral phase fcc stacked flips into skyrmion lattice around B _{ext} \sim <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
We present a computationally efficient general first-principles based method for spin-lattice simulations solids. Our is on combination of atomistic spin dynamics and molecular dynamics, expressed through Hamiltonian where the bilinear magnetic term expanded to second order in displacement, all parameters are computed using density functional theory. The effect first-order coupling magnon phonon dispersion bcc Fe reported as an example, seen be good agreement with previous performed...
Since thermal fluctuations become more important as dimensions shrink, it is expected that low-dimensional magnets are sensitive to atomic displacement and phonons than bulk systems are. Here we present a fully relativistic first-principles study on the spin-lattice coupling, i.e., how magnetic interactions depend displacement, of prototypical two-dimensional ferromagnet ${\mathrm{CrI}}_{3}$. We extract an effective measure coupling in ${\mathrm{CrI}}_{3}$, which up ten times larger what...
Combining theory with experiments, we study the phase stability, elastic properties, electronic structure and hardness of layered ternary borides AlCr2B2, AlMn2B2, AlFe2B2, AlCo2B2, AlNi2B2. We find that first three this series are stable phases, while AlCo2B2 AlNi2B2 metastable. show elasticity increases in boride series, predict AlFe2B2 more brittle, ductile. propose can be improved by alloying it cobalt or nickel, a combination them. present evidence these represent nanolaminated systems....
Persistent homology (PH) is a relatively new field in applied mathematics that studies the components and shapes of discrete data. In this paper, we demonstrate PH can be used as universal framework to identify phases classical spins on lattice. This demonstration includes hidden order such spin-nematic ordering spin liquids. By converting small number configurations barcodes obtain descriptive picture configuration space. Using dimensionality reduction reduce barcode space color leads...
We study the Fe/W(110) monolayer system through a combination of first principles calculations and atomistic spin dynamics simulations. focus on dispersion waves parallel to [001] direction. Our results compare favorably with experimental data Prokop et al. [Phys. Rev. Lett. 102, 177206], correctly capture drastic softening magnon spectrum, respect bulk bcc Fe. The suggested shortcoming itinerant electron model, in particular that given by density functional theory, is refuted. also...
The dynamics of a synthetic antiferromagnet (a metallic trilayer) have been explored and are shown to exhibit ultrafast switching on time scale tens ps. This conclusion is based first-principles, atomistic spin simulations. simulations performed at finite temperature, as well $T=0$ K (the macrospin limit), we observe marked temperature dependence the phenomenon. It that, reach very high speeds, it important that two ferromagnetic components oppositely directed external fields one another....
We examine the experimental absence of standing spin wave modes in thin magnetic films, by means atomistic dynamics simulations. Using Co on Cu(001) as a model system, we demonstrate that increasing number layers, optical branches predicted from adiabatic first-principles calculations are strongly suppressed, agreement with spin-polarized electron energy loss spectroscopy measurements reported literature. Our results suggest dynamical analysis Heisenberg is sufficient order to capture strong...
Originating from image recognition, methods of machine learning allow for effective feature extraction and dimensionality reduction in multidimensional datasets, thereby providing an extraordinary tool to deal with classical quantum models many-body physics. In this study, we employ a specific unsupervised technique -- self-organizing maps create low-dimensional representation microscopic states, relevant macroscopic phase identification detecting transitions. We explore the properties spin...
The dynamical behavior of the magnetism diluted magnetic semiconductors (DMS) has been investigated by means atomistic spin dynamics simulations. conclusions drawn from study are argued to be general for DMS systems in low concentration limit, although all simulations done 5% Mn-doped GaAs with various concentrations As antisite defects. magnetization curve, $M(T)$, and Curie temperature $T_C$ have calculated, found good correspondence results Monte Carlo experiments. Furthermore,...
The high Curie temperature multiferroic compound CuO has a quasidegenerate magnetic ground state that makes it prone to manipulation by the so-called ``order-by-disorder'' mechanism. First principle computations supplemented with Monte Carlo simulations and experiments show isovalent doping allows us stabilize phase in nonferroelectric regions of pristine material diagram reaching 250% widening ferroelectric window 5% Zn doping. Our results allow validate importance on promoting...
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...
The multiferroic compound CuO exhibits low-temperature magnetic properties similar to antiferromagnetic iron oxides, while the electronic have much more in common with high-${T}_{c}$ cuprate superconductors. This suggests novel possibilities for ultrafast optical excitation of magnetism. On basis atomistic spin dynamics simulations, we study effect phonon-assisted multimagnon absorption and photodoping on vicinity first-order phase transition from collinear spin-spiral order. Similar as...
We have carried out an experimental study of Ni-rich NiMn alloys in a series compositions across the multicritical point and determined phase diagram within that range. observed ferromagnetic long-range order with reentrant spin-glass/ferro-spin-glass for $x\ensuremath{\leqslant}25$, antiferromagnetic around $x\ensuremath{\sim}37$, gradual change from canonical spin-glass state to intermediate composition region. In explain observations, we examined physical properties density functional...
We demonstrate the use of Langevin spin dynamics for studying dynamical properties an archetypical spin-glass system. Simulations are performed on CuMn (20% Mn) where we study relaxation that follows a sudden quench system to low-temperature phase. The is modeled by Heisenberg Hamiltonian interaction parameters calculated means first-principles density-functional theory. numerically solving equations motion atomic spins. It shown governed, large degree, damping parameter in and size. For...
Field-induced switching of magnetization in a magnetic material is central to data-storage technologies. A theoretical investigation the microscopic dynamics atomic spins both antiferromagnetic and ferromagnetic systems leads fundamental insights into laser-induced switching.
Unlike other transition metals alloyed with a non-magnetic metal, alloys of Ni behave rather differently. This is because the fragility local magnetic moment on Ni. NiMo and NiW do not show any spin-glass phase. However, addition Fe can bolster We wish to study whether alloy Fe(3.3)Ni(83.2)Mo(13.5), chosen near composition where mean-field estimates suggest there could be phase, shows such phase or not.
The V-based kagome systems $A{\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ ($A=\mathrm{Cs}$, Rb, and K) are unique by virtue of the intricate interplay nontrivial electronic structure, topology, intriguing fermiology, rendering them to be a playground many mutually dependent exotic phases like charge-order superconductivity. Despite numerous recent studies, interconnection magnetism other complex collective phenomena in these has yet not arrived at any conclusion. Using first-principles tools, we...
We study the spin dynamics of a Heisenberg model at finite temperature in presence an external field or uniaxial anisotropy. For case anisotropy, our simulations show that macromoment picture breaks down. An effect which we refer to as spin-wave instability results nondissipative Bloch-Bloembergen-type relaxation where size changes and can even be made disappear. This mechanism is studied detail by means atomistic simulations.
Using the local density approximation plus dynamical mean-field theory (LDA+DMFT), we have computed valence-band photoelectron spectra and magnetic excitation of ${\mathrm{BiFeO}}_{3}$, one most studied multiferroics. Within DMFT approach, impurity problem is tackled by exact diagonalization solver. The solution within LDA+DMFT method for paramagnetic magnetically ordered phases produces result in agreement with experimental data on electronic structures. For comparison, also present results...