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In this letter, we provide a microscopic model for the ultrafast remagnetization of atomic moments already quenched above Stoner-Curie temperature by a strong laser fluence. Combining first principles density functional theory, atomistic…

Materials Science · Physics 2015-06-11 Raghuveer Chimata , Anders Bergman , Lars Bergqvist , Biplab Sanyal , Olle Eriksson

Spin-orbit torques induced by spin Hall and interfacial effects in heavy metal/ferromagnetic bilayers allow for a switching geometry based on in-plane current injection. Using this geometry, we demonstrate deterministic magnetization…

Damping effects form the core of many emerging concepts for high-speed spintronic applications. Important characteristics such as device switching times and magnetic domain-wall velocities depend critically on the damping rate. While the…

Materials Science · Physics 2020-12-08 Christian Tzschaschel , Takuya Satoh , Manfred Fiebig

We theoretically investigate the optically-induced demagnetization of ferromagnetic FePt using the time-dependent density functional theory (TDDFT). We compare the demagnetization mechanism in the perturbative and nonperturbative limits of…

Materials Science · Physics 2024-04-26 M. S. Mrudul , Peter M. Oppeneer

Engineering and controlling heat and spin transport on the femtosecond time-scale in spintronic devices opens up new ways to manipulate magnetization with unprecedented speed. Yet the underlying reversal mechanisms remain poorly understood…

Mesoscale and Nanoscale Physics · Physics 2026-02-04 Harjinder Singh , Alberto Anadón , Junta Igarashi , Quentin Remy , Stéphane Mangin , Michel Hehn , Jon Gorchon , Gregory Malinowski

We demonstrate optical control of magnons using femtosecond laser pulses by performing ab-initio real-time time-dependent density functional theory (TDDFT) simulations. We predict that the spin-wave dynamics in Fe$_{50}$Ni$_{50}$ can be…

Materials Science · Physics 2021-04-07 N. Singh , P. Elliott , J. K. Dewhurst , S. Sharma

Magnetism primarily describes the physics and materials science of systems presenting a magnetization -- a macroscopic order parameter characterizing electron angular momentum. The order parameter is associated with the electronic exchange…

Mesoscale and Nanoscale Physics · Physics 2018-10-11 Andrew D. Kent , Hendrik Ohldag , Herrmann Dürr , Jonathan Z. Sun

Real-time time-dependent density functional theory, in conjunction with the Ehrenfest molecular dynamics scheme, is becoming a popular methodology to investigate ultrafast phenomena on the nanoscale. Thanks to recent developments, it is…

Materials Science · Physics 2020-08-18 Jannis Krumland , Ana M. Valencia , Stefano Pittalis , Carlo A. Rozzi , Caterina Cocchi

Optically Pumped Magnetometers use light to drive an atomic vapor into a Non-Equilibrium Steady State for sensing. This kind of state is achieved when spin-exchange collisions, together with optical pumping, dominate the relaxation…

Quantum Physics · Physics 2026-04-13 A. F. Sousa , C. H. S. Vieira , H. M. Florez

We demonstrated that final states of ultracold scattering between atom and molecule can be selectively produced using dynamic magnetic fields of multiple frequencies. The mechanism of the dynamic magnetic field control is based on a…

Quantum Physics · Physics 2022-07-13 Hanwei Yang , Zunqi Li , Songbin Zhang , Lushuai Cao , John Bohn , Shutao Zhang , Haitan Xu , Gaoren Wang , Zheng Li

Ultrafast magnetization dynamics in metallic heterostructures consists of a combination of local demagnetization in the ferromagnetic constituent and spin-dependent transport contributions within and in between the constituents. Separation…

The direct manipulation of spins via light may provide a path toward ultrafast energy-efficient devices. However, distinguishing the microscopic processes that can occur during ultrafast laser excitation in magnetic alloys is challenging.…

We utilize simulations of electron scattering by a chain of dynamical quantum spins, to analyze the interplay between the spin transfer effect and the magnetization dynamics. We show that the complex interactions between the spin-polarized…

Materials Science · Physics 2021-04-21 Neil Tramsen , Alexander Mitrofanov , Sergei Urazhdin

We study the dynamical magnetization process in the ordered ground-state phase of the transverse Ising model under sweeps of magnetic field with constant velocities. In the case of very slow sweeps and for small systems studied previously…

Other Condensed Matter · Physics 2009-11-13 Seiji Miyashita , Hans De Raedt , Bernard Barbara

Ultrashort laser pulses provide the fastest known way to switch magnetic order. Such excitation commonly creates nanometer-scale domains, even after homogeneous illumination when the position of nucleated domains is not externally defined.…

Spin-orbit coupling stands as a pivotal determinant in the realm of condensed matter physics. In recent, its profound influence on spin dynamics opens up a captivating arena with promising applications. Notably, the topological…

Mesoscale and Nanoscale Physics · Physics 2024-08-06 Taekoo Oh , Naoto Nagaosa

We propose a time-dependent approach to investigate the motion of electrons in quantum pump device configurations. The occupied one-particle states are propagated in real time and used to calculate the local electron density and current. An…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 G. Stefanucci , S. Kurth , A. Rubio , E. K. U. Gross

A concise review of observations of the $\alpha$ dynamo effect in laboratory plasmas is given. Unlike many astrophysical systems, the laboratory pinch plasmas are driven magnetically. When the system is overdriven, the resultant…

Astrophysics · Physics 2021-06-29 Hantao Ji , Stewart C. Prager

Starting with an extended version of the Anderson lattice where the f-electrons are allowed a weak dispersion, we examine the possibility of a Mott localization of the f-electrons, for a finite value of the hybridization $V$. We study the…

Strongly Correlated Electrons · Physics 2009-11-13 C. Pepin

We derive the fundamental equations of an optimal control theory for systems containing both quantum electrons and classical ions. The system is modeled with Ehrenfest dynamics, a non-adiabatic variant of molecular dynamics. The general…

Chemical Physics · Physics 2015-06-16 Alberto Castro , E. K. U. Gross