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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

Time-dependent density functional theory is implemented in an all electron solid-state code for the case of fully non-collinear spins. We use this to study laser induced demagnetization in Fe, Co and Ni. It is shown that this…

Materials Science · Physics 2014-06-26 K. Krieger , J. K. Dewhurst , P. Elliott , S. Sharma , E. K. U. Gross

When a laser pulse excites a ferromagnet, its spin undergoes a dramatic change. The initial demagnetization process is very fast. Experimentally, it is found that the demagnetization time is related to the spin moment in the sample. In this…

Materials Science · Physics 2016-11-11 G. P. Zhang , M. S. Si , Thomas F. George

Laser-induced ultrafast demagnetization is a phenomenon of utmost interest and attracts significant attention because it enables potential applications in ultrafast optoelectronics and spintronics. As a spin-orbit coupling assisted magnetic…

The dynamics of ultrafast demagnetisation in 3$d$ magnets is complicated by the presence of both spin ${\v S}$ and orbital ${\v L}$ angular momentum, with the microscopic mechanism by which the magnetic moment is redistributed to the…

Materials Science · Physics 2021-09-01 J. K. Dewhurst , S. Shallcross , P. Elliott , S. Eisebitt , C. v. Korff Schmising , Sangeeta Sharma

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

Optically induced demagnetization of 3d metallic ferromagnets proceeds as fast as ~100 fs and is a crucial prerequisite for spintronic applications, such as ultrafast magnetization switching and spin transport. On the 100 fs time scale, the…

The ultra-fast demagnetization of small iron clusters initiated by an intense optical excitation is studied with time-dependent spin density functional theory (TDSDFT). In particular we investigate the effect of the spin-orbit interaction…

Mesoscale and Nanoscale Physics · Physics 2016-07-27 Maria Stamenova , Jacopo Simoni , Stefano Sanvito

Induced by an ultra-short laser pulse, the electronic structure of a material undergoes strong modifications leading to a fast demagnetization in magnetic materials. Induced spin-flip transitions are one of the reasons for demagnetization,…

Materials Science · Physics 2024-04-29 Sergiy Mankovsky , Svitlana Polesya , Hubert Ebert

In past decades, ultrafast spin dynamics in magnetic systems have been associated with heat deposition from high energy laser pulses, limiting the selective access to spin order. Here we use a long wavelength terahertz pump optical probe…

Materials Science · Physics 2021-06-04 Hovan Lee , Cedric Weber , Manfred Fähnle , Mostafa Shalaby

The ultrafast demagnetization (UFD) dynamics of itinerant ferromagnets is theoretically investigated as a function of the characteristics of the initial laser excitation. A many-body pd-band Hamiltonian is considered which takes into…

Strongly Correlated Electrons · Physics 2019-07-10 W. Töws , G. M. Pastor

Reducing energy dissipation while increasing speed in computation and memory is a long-standing challenge for spintronics research. In the last 20 years, femtosecond lasers have emerged as a tool to control the magnetization in specific…

Laser-induced demagnetization is theoretically studied by explicitly taking into account interactions among electrons, spins and lattice. Assuming that the demagnetization processes take place during the thermalization of the sub-systems,…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 A. Manchon , Q. Li , L. Xu , S. Zhang

The ability to control spins in semiconductors is important in a variety of fields including spintronics and quantum information processing. Due to the potentially fast dephasing times of spins in the solid state [1-3], spin control…

The ultimate control of magnetic states of matter at femtosecond (or even faster) timescales defines one of the most pursued paradigm shifts for future information technology. In this context, ultrafast laser pulses developed into extremely…

Mesoscale and Nanoscale Physics · Physics 2022-03-15 Hanan Hamamera , Filipe Souza Mendes Guimarães , Manuel dos Santos Dias , Samir Lounis

We show that quantum optimal control theory (OCT) and time-dependent density-functional theory (TDDFT) can be combined to provide realistic femtosecond laser pulses for an enhanced ionization yield in many-electron systems. Using the…

Atomic Physics · Physics 2015-06-17 M. Hellgren , E. Rasanen , E. K. U. Gross

Irradiating a ferromagnetic material with an ultrashort laser pulse leads to demagnetization on a femtosecond timescale. We implement Elliott-Yafet type spin-flip scattering, mediated by electron-electron and electron-phonon collisions,…

Materials Science · Physics 2011-08-29 Benedikt Y. Mueller , T. Roth , M. Cinchetti , M. Aeschlimann , B. Rethfeld

The discovery of femtosecond laser-induced ultrafast demagnetization in 1996 opened a new field, femtomagnetism, in which magnetic order can be quenched on timescales shorter than a picosecond. This seminal observation revealed that angular…

Materials Science · Physics 2026-04-29 Quentin Remy , Stéphane Mangin

Exploring ultrafast magnetization control in two-dimensional (2D) magnets through optically driven coherent phonons has been well-established. Yet, the microscopic interplay between spin dynamics and lattice degrees of freedom remains less…

Computational Physics · Physics 2024-03-25 Zhaobo Zhou , Min Li , Thomas Frauenheim , Junjie He

This year the discovery of femtosecond demagnetization by laser pulses is 20 years old. For the first time this milestone work by Bigot and coworkers gave insight in a very direct way into the time scales of microscopic interactions that…

Mesoscale and Nanoscale Physics · Physics 2016-09-14 J. Walowski , M. Münzenberg
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